Splash overhaul

[mrjackv]

We have a progress bar :tada: (should fix #8)

Minor things that have changed:

• config.ini: new config options
  • splash_preference: order in which splashes are going to be tried
  • zenity_bigpicture: allow zenity as splash in bigpicture mode
• util.install_from_zip has been moved to download in an effort to slim down utils and since it made more sense to be there
• metal slug fixes and doom have been modified to use download.install_from_zip, install_from_zip now has a filesha parameter like in the metal slug fixes

How the progress bar works

1. TrackProgress is created in progress.py, it has an internal registry
2. fix.py imports all the modules that have TrackProgress-decorated functions, the decorator is invoked and the internal registry is populated with fully-qualified function names that are being decorated (e.g. protonfixes.utils.protontricks)
3. When fix.py finds a suitable fix, it loads the .py file into progress.parse_fix, this in turn runs ast (static parsing) and outputs a list of fully-qualified function calls in the specified .py file, it then filters out any that are not in the TrackProgress registry and sets the TOTAL_STEPS variable
4. Once a fix's main() is actually called the decorator indirectly calls functions in splash.py to update the title and increment the progress bar.
5. splash checks which method it used for displaying progress and uses an appropriate way to updated it. (CEF needs a Queue since it runs on a separate process)

[pchome]

enable_splash = false config option is broken now.

[mrjackv]

Whoops must have forgotten while refactoring :grimacing: PR already published