feat: ability to configure image icon sizes

Adds `icon_size` option to following widgets:

- `clipboard`
- `launcher`
- `music`
- `workspaces`

Also adds `cover_image_size` option to `music`.

docs/modules/Launcher.md

@@ -14,6 +14,7 @@ Optionally displays a launchable set of favourites.
 | `favorites`  | `string[]` | `[]`    | List of app IDs (or classes) to always show at the start of the launcher                            |
 | `show_names` | `boolean`  | `false` | Whether to show app names on the button label. Names will still show on tooltips when set to false. |
 | `show_icons` | `boolean`  | `true`  | Whether to show app icons on the button.                                                            |
+| `icon_size`  | `integer`  | `32`    | Size to render icon at (image icons only).                                                          |
 
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