[TYPO3-core] Refactor sys_notes

[Georg Ringer]

Hi,

I will restructure the sysext sys_note and make it nice and shiny, see
http://forge.typo3.org/issues/26796 for the screens.

However I would like to remove the previous implementation completly
which can be currently found here:
- class.db_list.inc -> showSysNotesForPage() for the list module
- db_layout.php > for the page module
- class.tx_cms_webinfo for the info module

and introduce new hooks there which could be used from other exts too
and will be used by ext:sys_note

any objections?

Georg