feat: Add VerticalTileLayout

[defer]

Summary

A Vertical tiling layout which is tailored for portrait orientated monitors but might have use cases in landscape as well.

The intended behavior is for the master area to take a fixed (but configurable via shortcut) percentage of the screen and for the remaining panes to split the remaining space. Multiple masters are supported and will share the master area equally.

An example of two masters, followed by a stack of two panels:

 ---------
|         |
|   M1    |
|         |
| ------- |
|         |
|   M2    |
|         |
 ---------
|    1    |
 ---------
|    2    |
 ---------

The layout is disabled by default.

Breaking Changes

No

UI Changes

Before	After
Before, there was nothing...

Test Plan

1. Go to layouts, enable vertical tile, apply.
2. Change to vertical tile.
3. Presto.

Related Issues

Closes #397

[gikari]

A Vertical tiling layout which is tailored for portrait orientated monitors but might have use cases in landscape as well.

Since its intended purpose is for using with rotated vertical monitors, is it possible to theoretically achieve the behavior of this layout, using an existing one, but rotating it?

[defer]

I guess it could be achieved if a rotated tile layout kept the non-master stack vertical rather than horizontal but didn't want to introduce such breakage.

[krshrimali]

I love this! Thanks for your work, @defer! @gikari - would love if this can be merged (if it looks okay to you and if you have the time) <3