Allow easy navigation between commands run in the terminal

[Tyriar]

Related: #20676

[Tyriar]

I just added the following commands:

workbench.action.terminal.scrollToPreviousCommand
workbench.action.terminal.scrollToNextCommand
workbench.action.terminal.selectToPreviousCommand
workbench.action.terminal.selectToNextCommand

On macOS they are bound to cmd+up/down and cmd+shift+up/down, scroll one line up/down have been moved to cmd+alt+pgup/pgdown.

They are unbound by default on Linux/Windows keybindings.

[Tyriar]

Moved the displaying of glyphs for commands and flashing the line when scrolling to a command to #46561