Allows the user to resize panes using hotkeys

Changes:
- Adds 4 hotkeys for resizing panes horizontally and vertically
- Updates the config files (default not set)
- Updates the window settings to allow the user to modify the pane
  resize increments

tabby-core/src/configDefaults.yaml

@@ -12,6 +12,7 @@ appearance:
   frame: thin
   css: '/* * { color: blue !important; } */'
   opacity: 1.0
+  paneResize: 0.1
   vibrancy: false
   vibrancyType: 'blur'
 terminal: