UI Clean-up, Overhaul and Guidelines

• Stop the alternating between colors in lists, instead have a highlighted accent title bar, and a uniform children with tiny accented separators which would look way better.
• Replace all massive lists with dropdown menus and single entries.
• Add preview and browse to all icon/image selectors, the browser should have 2 tabs icon and image file.

* icon takes the image texture from the current otter icon theme icon://pika-logo.

• image takes the texture from a static file path provided by user file:///home/cosmo/Pictures/pika-logo.svg.

If you put file path it reads a file, if you just put the icon name it searches active icon theme, not as explicit but hey good enough for me.

• drop all the font image stuff from settings they are ugly and non aligned.
• Write actual HIG guidelines for all future applications and community contributions.
• Migrate all current icon selection from filepath to file://filepath (the third / is from the filepath).
• Add an enable system animations option, and makes everything animated

Optional:

• support home dir abstraction so configs don't explode when a user changes his username file://~//Pictures/pika-logo.svg ~/Pictures/pika-logo.svg
• animation speed settings.