Introduce BookmarkRemovalManager vestore;

to manage the smart deletion of bookmarks.
Revert "Introduce BookmarkRemovalManager vestore;"

This reverts commit ab1453b4fbd693144a54b80003c585ff976c6f3c.
Introduced the generic 'Remove' functions everywhere.

The previous way was not good, we will introduce a new class to do hard
stuff for the user.
Renamed BMMgr::DeleteBookmark to RemoveBookmark. The 'Remove' function
in all Isubmanagers just remove what they control. Also some other
Remove functions were introduced.
Introduce BookmarksBusinessLogic.

Used for deleting bookmarks right now. Should be used for bookmark
retrieval and saving in the future.