* Added tests for `LightRenderer`

* Added common SHIFT, ALT and ALT+SHIFT key sequences

* Added common CTRL key sequences

* Added common CTRL+ALT, CTRL+SHIFT, CTRL+ALT+SHIFT key sequences

* Added proper xterm META modifier handling

according to https://github.com/joejulian/xterm/blob/defc6dd5684a12dc8e56cb6973ef973e7a32caa3/input.c#L357-L375

* Fix `ctrl-backspace` and `ctrl-alt-backspace`

* Fix broken tcell tests on windows by swallowing Resize events

* Added tests for  FullscreenRenderer

* Removed own fork of tcell and updated tcell to 2.9.0

tcell 2.9.0 is needed for `Ctrl-Alt-*` and `Ctrl-Alt-Shift-*` shortcuts in Windows

* Replace conditional checks with switch statements to improve readability

* Replace long conditionals with constant slices to improve readability

* Bind `ctrl-bspace` (`ctrl-h`) to `backward-delete-char` by default

Since we now distinguish between Backspace and Ctrl-Backspace, Ctrl-Backspace should trigger the same action as Backspace by default. In that way nothing changes for the user but you can bind other actions to Ctrl-Backspace when desired.

* 'enter' instead of 'ctrl-m'
* 'space' instead of ' '

  # This will no longer cause 'Vim: Warning: Output is not to a terminal'
  fzf --bind 'enter:execute:vim {}' > /tmp/foo

Close #2932

Co-authored-by: Emil Vanherp <emil@vanherp.me>

CtrlH events are still sent when appropriate. I have adjusted
FullscreenRenderer to match the LightRenderer's behaviour, which seems
to be correct.