Resolve "Nutmeg-related changes"

Closes #2

See merge request !2

Resolve "Initial Totem setup"

Closes #1

See merge request !1

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Co-authored-by: Renovate Bot <bot@renovateapp.com>

chore(deps): update dependency immer to 9.0.6 [security]

BREAKING CHANGE: This PR performs some surgery on the code that loads our New Relic browser agent into our MFEs. Because of that, we're making this a breaking change and reminding MFE application owners to verify their app is still sending data to New Relic after updating. We have tested these changes in the frontend-build/example app, but you're responsible for double-checking your app's integration.

Also:

cleaning up a warning about HotModuleReplacementPlugin, which stated that the plugin doesn't need to be included explicitly if hot: true has been specified.
bumping webpack-dev-server into a real release, instead of a beta.
Adding an .nvmrc file set to node 12.

Commit messages:

* fix: build cleanup and remove dependency on html-webpack-new-relic-plugin

Also cleaning up a warning about HotModuleReplacementPlugin and bumping webpack-dev-server into a real release, instead of a beta.

* fix: cleaning up lint and changing import/export to be node-friendly

* feat!: updating new relic script to latest version

BREAKING CHANGE: Applications should mindfully update to this version and ensure that their New Relic tracking is still working.  The snippet has been changed but can't easily be tested in development.

* fix: review feedback

1. Pre-pending the NR script to the head
2. Adding a detailed comment about how to update the snippet
3. Adding a snippet version number (1212)

* feat: pulling in tests and license from html-webpack-new-relic-plugin

* build: add an nvmrc pinning the repo to v12 of node

* test: linting the test file for html-webpack-new-relic-plugin

feat: make it possible to disable NewRelic globally

By defining the `ENABLE_NEW_RELIC='false'` environment variable, the new relic
logging integration will be disabled, which is a must-have for most non-edX
platforms.

Close https://github.com/openedx/frontend-wg/issues/14

Co-authored-by: Renovate Bot <bot@renovateapp.com>
Co-authored-by: Phillip Shiu <pshiu@users.noreply.github.com>

Co-authored-by: Renovate Bot <bot@renovateapp.com>

fix(deps): update babel monorepo

This adds a fairly simple mechanism to the webpack config that resolves a package named env.config to a local env.config.js file in the app. If such a file doesn't exit, it falls back to an empty env.config.js file in frontend-build so that webpack doesn't break.

This is the groundwork required for us to use JS-based environment configuration. This would have numerous benefits, most importantly, letting us use non-string values in our config (like booleans and numbers) as well as importing other resources to be used as config, such as alternate implementations of services in frontend-platform.

Note: The code in this PR makes it technically possible for us to optionally import such a file, but the mechanism isn't really useful yet because it requires support in both frontend-platform and our build processes. Stay tuned.

Commits:

* feat: adding the basic mechanism for using a JS file for env config

- Add an alias and fallback for "env.config" in the webpack.common.config.js file.
- Put an empty fallback file in the config directory in case an MFE doesn't specify its own.

The idea is that an MFE (or probably frontend-platform) can provide an env.config.js file which will be linked in if it exists.  This is an alternative to .env files.

* test: use a sample env.config.js file in the example app

This commit also organizes the tests in the example app a bit.

* fix: fixing eslint mis-configuration

Also cleaning up example app linting errors.

* docs: adding an ADR describing the decision to move to JS env config

* test: fixing broken tests and jest config

The jest config needs to have the same sort of fallback behavior that webpack uses.  It doesn't use webpack itself, just babel.

* refactor: use false value for fallback instead of a file

If the "fallback" webpack resolve parameter is set to `false`, then it resolves the module with an empty object.  This is perfect for us.

It also lets us move our fallback file into the jest subdirectory, since we still need a physical file when jest gets run.

* docs: mention tubular in ADR

* fix: removing unnecessary .babelrc.js file

We don't actually need this file in order to run the build; it pulls it from the config directory on its own.

* test: fixing SASS variable name in example styles

Making the variable name match the element it's being applied to.

fix: update webpack cli

v4 of webpack-dev-server has a breaking change where the 'transportMode' configuration for the dev server was changed to 'webSocketServer', effectively.

See migration guide here: https://github.com/webpack/webpack-dev-server/blob/master/migration-v4.md

* fix: use webpack 5 compatible new relic source map plugin

* fix: update plugin import to new package

* build: pin new dependency

Recent changes to devstack allow installation of local
NPM packages for MFEs running in devstack. However,
it requires shared NPM packages to be placed at a specific
location: ../src. Update this repo's docs to reflect that.

TNL-8407

This updates the @babel/preset-react configuration to use the new JSX transform, which no longer requires React to be imported into source files.

It also updates our eslint-config to no longer require that React be imported into source files as well.

This works because our babel (7.9.0+) and react (16.14.0+) versions are high enough that they can take advantage of the new JSX transform.

BREAKING CHANGE: Note that this means this version of frontend-build has a new peer dependency on react > 16.14.0, to ensure that it has the new JSX transform available.

feat: Fix/improve hot reloading 🚀, support SCSS exports again, and add local alias overrides to webpack.dev-stage.config.js (#191)

* fix: support js imports of scss exports again

* feat: fix hot module replacement, add fast refresh webpack plugin

* fix: add local aliases to webpack.dev-stage.config.js

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