feat(shortcuts): add helper written in egui

This commit adds a simple egui helper application which shows a list of
shortcuts defined in a user's whkdrc file. Parsing AHK files is not
supported.

In addition to listing out shortcuts defined in the whkdrc file, the top
line allows users to add filter a filter to narrow down the list of
commands and key bindings to the ones they are interested in.

A new komorebic command "toggle-shortcuts" has been introduced which
will first attempt to kill "komorebi-shortcuts.exe", and then exit if
the kill signal was successful (ie. a process was closed), or proceed to
open "komorebi-shortcuts.exe" if the kill signal was not successful (ie.
no process was closed, so we should open one).

"komorebi-shortcuts.exe" has been added as a floating application in
lib.rs to allow for users to use the "komorebic move" command to
manipulate its position via their existing keyboard bindings.

docs/whkdrc.sample

@@ -5,6 +5,8 @@
 alt + o                 : taskkill /f /im whkd.exe; Start-Process whkd -WindowStyle hidden # if shell is pwsh / powershell
 alt + shift + o         : komorebic reload-configuration
 
+alt + i                 : komorebic toggle-shortcuts
+
 # App shortcuts - these require shell to be pwsh / powershell
 # The apps will be focused if open, or launched if not open
 # alt + f                 : if ($wshell.AppActivate('Firefox') -eq $False) { start firefox }