LibGUI: Implement linewise visual mode for VimEditingEngine

[huttongrabiel]

Visual line mode is almost identical to visual mode except for it operates on whole lines. Movement up/down with k/j selects whole lines and left/right with l/h has no affect. Shift+V enters visual line mode.

[huttongrabiel]

Vim documentation for "linewise visual" mode: linewise visual

[networkException]

The commit title isn't very descriptive, maybe include that this change is for VimEditingEngine

[AtkinsSJ]

This has conflicts.

[huttongrabiel]

TBH, I forgot I opened this. Looks like somebody else got it done, #15016 , :ninyak: . Will close :^)