Make the module extendable with plugins

MR wasn't mergeable anymore due to added commit: https://git.drupalcode.org/project/coffee/-/commit/371eadfd13e34d053aba9...

This has now been fixed.

I altered the default config so it's identical to the current situation for the end user.
Extra plugins (content + people) can be enabled and configured afterwards.

This is a great idea.

Latest commit moves the responsibility of escaping the search result labels to the controller, rather than every plugin having to do it separately.
This also ensures any results added through the (perhaps deprecated after introducing the plugin type?) coffee_commands-hook.

Could a maintainer please take a look at this issue?
It doesn't change the module's initial installation state, and it adds a lot of possible functionality.

I think this could really spearhead this module's already superb usefulness.

Agreed with #6 ✨ Make the module extendable with plugins Active ! Great idea. NOTE: content is already supported if you refer to admin/content and such overviews. But if it refers to content like node/234 I would be careful on larger projects (index size).

Regarding #8 ✨ Make the module extendable with plugins Active : start testing now ...