* Remove checkmark for official plugins
* Add author for plugin, which is By Discourse for all discourse
and discourse-org github plugins
* Link to meta topic instead of github repo
* Add experimental flag for plugin metadata and show this as a
badge on the plugin list if present
---------
Co-authored-by: chapoi <101828855+chapoi@users.noreply.github.com>
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 reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
