Allow more customizable keybindings for chatview.

[roket1428]

What do you want

Allow users to bind keys for selecting text (arrow keys) and scrolling up and down (pageup/pagedown).

Why

I don't want to use arrow keys to select a text or pageup and pagedown to go up and down in chatview. Those keys are so far to reach and I can customize most of the keys, why not others?

Implementation hints

Just add couple more fields to CTRL+K section to bind those keys.

Edit

Would be nice to be able to customize move up and down functionality of servers and channels too. :3 <3