Replace content-for using a Vite plugin

[BlueCutOfficial]

This PR moves {{content-for}} from stage 2 to stage 3:

We no longer replace the {{content-for}} snippets in the index.html during the build of the rewritten app. Instead, we leave the {{content-for}} in place and it's a new Vite plugin that performs the replacement. To do so, the Vite plugin relies on a new file content-for.json output during the pre-build.

Breaking change

The new approach supposes that Embroider knows in advance what types of {{content-for}} are provided by the addons, because the Broccoli plugin that builds the dictionary needs to be agnostic from rewritten-app/index.html if we don't want to be tied with stage 2.

The new build option availableContentForTypes allows to extend the list of {{content-for}} types in case an addon provides something custom. For instance, let's suppose your app relies on a classic addon that provides {{content-for "custom"}}, you should add the following build option so the content can be replaced:

// ember-cli-build.js
const EmberApp = require('ember-cli/lib/broccoli/ember-app');
const { prebuild } = require('@embroider/compat');

module.exports = function (defaults) {
  const app = new EmberApp(defaults, {});
  return prebuild(app, {
    availableContentForTypes: ['custom'],
  });
};

[BlueCutOfficial]

The canary-static-app error sounds a bit like the tests not being present but I am not sure how it's related to the PR and how it happens because the command pnpm test: production uses the option FORCE_BUILD_TESTS: 'true'.

The canary-vite-app-basics errors comes from a test using the command node ./scripts/run-tests.mjs that executes the given test file. I am not familiar with that part.

[mansona]

Fantastic work 🎉