Add next/previous tab hotkeys

[lkiesow]

The old admin ui featured two hotkeys that would let you move forward and backward between the different steps in a create modal. It could be nice to have this again. We had an attempt at doing this in #830, but that faced some issues.

[EnsiyehE]

Hello Lars & Arne,

I have tried to find a solution for this issue ,

but during that i have found another issue underhood , which i thought to state it here and ask your opinion if it would be better to open a seprate issue or work on the same branch ,

when a user submit a title and wants to press Enter ( to temporary take the auto focus from the first input field in the modal addEvent and edit an event ) , or by Pressing Escape key on the keyboard , sometimes we lose the focus trap of the modal .. which i think it is not a good Ux To see for anyone ( The focus would be gone to the browser elements so to say )

could you please try this and look and my PR and share your opinions regarding both ?

the PR Is #1441

thanks for your time
bests
Ensiyeh