Revamping of notification watch buttons

We changed the way one can decide to watch a location in XWiki.

Starting with this release, a button is present in all pages next to the edit button. This buttons shows by default the current state of the page:

• Followed: if you're following the page to receive notifications about it
• Blocked: if you're blocking the page to not receive notifications about it
• Not set: in case you haven't set any preferences for watching or blocking it
• Custom: this appear if you have some preferences corresponding to that page but that are specific to some specific event types, or some specific formats (e.g. you only want to receive some notifications by email for a specific location).

If you click on the button, you will obtain a modal window explaining the current state (e.g. you might have a page followed because you are actually following a space containing that page), and allowing you to perform actions to change that state.
That modal also contains a link to access directly the notification filters settings: this is useful if you want to properly review your settings or perform custom actions from there. Note that if the current state is custom you can only perform actions from the notification filters settings.