patch-6 XWIKI-10449: improve top menu of flamingo

Add hyperlink to access on webhome of wiki and space and Page on top menu of flamingo.

The problems with this pull request are: 
A. we mess with the Boostrap standard - let's say this is acceptable but we will need to write all the rules for the responsive cases (aka fix the menu when on mobile)

B. in order to expand the menu the user needs to explicitly press on the arrow, which is a very small area compared to the whole entry. This is very problematic for Mobile usage, since it's hard to touch target small areas, but let's say we have the dedicated view for this.