[TASK] Improve Install Tool UX

Implemented card layout and modals instead of gridder.
Action buttons like clear all cache trigger it's action now directly.
Upcomming Notfications are displayed via backend notifications.
Content for modals is completly loaded via ajax calls. The icon api
is now available for the standalone mode of the install tool.
"libs/chosen" is imported in backend.scss to display proper styling of
chosen selects in modals.

Releases: master
Resolves: #84772
Change-Id: Ib5efbcd45c00b9c3dc973446e3fc1ef39c1f1146
Reviewed-on: https://review.typo3.org/56065


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Benjamin Kott <benjamin.kott@outlook.com>
Tested-by: Benjamin Kott <benjamin.kott@outlook.com>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>