Remove unused code related to homepage

[allyoucanmap]

Description

see #10731 (review)

I noticed that many things has not been removed. What is the policy we want to use?

• Deprecate: in this case, we need to indicate the plugins deprecated, and sooner deleted, with old components that are not used anymore.
• Delete: in this case we should remove the plugins at all, so the depending project are forced to migrate.

We already marked the deprecated plugins but it will be better to remove all the unused code resulted after the update of the new homepage

What kind of improvement you want to add? (check one with "x", remove the others)

• Minor changes to existing features

Other useful information