Add emacs keybindings

[RomanNikitenko]

What does this PR do?

Move Commands:

• Move forward by Ctrl+f
• Move backward by Ctr+b
• Move to the next line by Alt+n (Ctrl+n - new tab in browser)
• Move to the previous line by Ctrl+p
• Move to the beginning of line by Ctrl+a
• Move to the end of line by Ctrl+e
• Move forward by one word unit by Alt+f
• Move backward by one word unit by Alt+b
• Move to the end of buffer by Alt+>
• Move to the beginning of buffer by Alt+<
• Scroll down by one screen unit by Ctrl+v
• Scroll up by one screen unit by Alt+v
• Jump to line (command palette) by Alt+g g

Edit Commands:

• Delete right (DEL) by Ctrl+d
• Delete left (BACKSPACE) by Ctrl+h
• Delete word by Alt+d
• Kill to line end by Ctrl+k
• Select All by Ctrl+x h
• Undo by Ctrl+x u or Ctrl+/
• Toggle line comment in and out by Ctrl+;
• Toggle region comment in and out by Alt+;

Search Commands:

• Search forward by Ctrl+s
• Search backward by Ctrl+r
• Add selection to next find match by Ctrl+Alt+n

Other Commands:

• Open command palette by Alt+x
• Save by Ctrl+x Ctrl+s
• Quick open a file by Ctrl+x b

Video:
https://www.youtube.com/watch?v=Oh48iTA-2lg&t=19s

What issues does this PR fix or reference?

eclipse-che/che#9244

Signed-off-by: Roman Nikitenko [email protected]