[TASK] Forms: Input/textarea :focus style

Brings a discreet :focus style for fields and buttons in ice
blue to complement our favorite TYPO3 orange.

Is introduced for all input fields, input submit & input reset,
buttons and textareas - generally and without exceptions.

Select and multi select fields do not get this focus definition.

Resolves: #55901
Releases: 6.2
Change-Id: I49d958199e29560a766f4687aa76541d07702901
Reviewed-on: https://review.typo3.org/27562
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind