Color Picker should be refactored into `App.ColorPicker`

[Marak]

The current color picker is cool, but it acts like a popup window and should instead act like a regular desktop window.

To do this, we'll want to create a new app called App.ColorPicker which shows the color picker.

If App.ColorPicker is opened from anywhere ( such as Themes / Wallpaper Apps ), it will have a context of an input such as "wallpaper_color".

If App.ColorPicker is opened as a stand-alone app ( without context and not from any input ), then the color picker can just display and do nothing ( for now ).