Improve the UI of Comments: Show & filter annotations

Proposal link https://design.xwiki.org/xwiki/bin/view/Proposal/CommentsAnnotations#HProposal233:Show26filterannotations

Improvements
#1 Showing annotations enabled by default.
#2 Seeing annotations should be enabled by default. Disabling and filtering annotations is done from the same menu item (any page> More > Annotate), but the UI is a bit different.
#3 Users are shown one after another horizontally, saving more vertical space between the page title and the content. For lots of user, the list wraps on the next line. The users are ordered alphabetically by their first name so the author can find a certain person in a long list easily.
#4 For long lists, we should also have a Select all and Unselect all button.
#5 This UI would also have an "x" icon to close it in 1 click. This way the user doesn't have to do 2 clicks and quite a lot of mouse movement to not see this UI component (as it is currently)

Look: