As of #23867 this is now a real package, so updating the imports to
use the real package name, rather than relying on the alias. The
name change in the package name is because `I18n` is not a valid
name as NPM packages must be all lowercase.
This commit also introduces an eslint rule to prevent importing from
the old I18n path.
For themes/plugins, the old 'i18n' name remains functional.
For the admin plugin list we want to be able to link to
a meta topic for plugins, but we have no standard way to
do this at the moment. This adds support for meta_topic_id
alongside other plugin metadata like authors, URL etc,
that gets built into a Meta topic URL in the serializer.
This commit contains a few improvements:
* Use LinkTo instead of a button with a weird action referencing the
controller to navigate to the filtered settings for a plugin
* Add an AdminPlugin model with tracked properties and use that when
toggling the setting on/off and in the templates
* Make it so the Settings button for a plugin navigates to the correct
site setting category instead of always just going to the generic
"plugins" one if possible
