Remove app directory page and associated links

[ryankeairns]

I decided against using the feature catalog/directory data since it is mostly out of date anyway and would require more work to integrate with the existing app results.

That makes sense to me. @ryankeairns one thing we discussed earlier is that we can remove the app directory link from the home page and Kibana overview page once the feature results provider is in place. With these changes, are we good to remove the link? I realize the home page is powered by it at the moment, so I'm fine with simply removing the link from the home page.

Originally posted by @alexfrancoeur in #72680 (comment)

Taking this a step further than the original post, we should try to remove the entire directory UI as suggested below.

[elasticmachine]

Pinging @elastic/kibana-design (Team:Kibana-Design)

[myasonik]

Should we create a separate issue for actually dismantling the app directory stuff then? It's just a bunch of tech debt sitting around otherwise.

[ryankeairns]

Should we create a separate issue for actually dismantling the app directory stuff then? It's just a bunch of tech debt sitting around otherwise.

That would be much smarter, yes. I don't know what all that entails, but I could take a swing at it.