* feat(e2e): add language extension to setup
This adds a slimmed-down version of the Spanish Language Pack and also
adds a `languagepacks.json` to the e2e `workspaceDir` which allows use
to run a test suite passing the `--locale es` flags to simulate a
different display language.
* feat: add e2e test for display language patch
This tests loading code-server in Spanish using the `--locale` flag.
* fixup!: use JSON.stringify for readability
* fixup!: add comment about langaugepacks temp fix
* fixup!: slim down translations
* fixup!: slim down package.json for lang. ext
