[TASK] create blank session if none exists in suggestform action

[TASK] change forward to redirect to drop unwanted parameter and get
       a clean form when calling save action directly
[TASK] add flash message after saving suggested session
[TASK] redirect after save to form action to prevent reload
       spamming / removed now unused suggest save template
[TASK] disable default flash error messages
[TASK] changeing css classes on error messages for better targeting
       on modular based css
[TASK] adding fallback if no translation for error messages exists

Change-Id: I000aead06c0c668e481da311e8cfb8dc10009d1a
Reviewed-on: https://review.typo3.org/24116
Reviewed-by: Benjamin Kott
Tested-by: Benjamin Kott