Implementation of adjustable widget sizes

[DOD-101]

While working on #278 I have come across two different way to implement the setting of different widget sizes in the config.

Option 1

Have two config values album width & playlist width and have them be the percentage values used in the layout.

Pros

• Super simple to understand

Cons

• Having two values to configure the size of the widgets seems very unclean
• It is easily possible to write values which are too large and would then cause errors, which need to be checked for

Option 2

Add a ration to the config such as 3:2:4, which will define the size of the different widgets. See: CSS-Flex

Pros

• One value to define the size of all relevant widgets
• Errors can be entirely avoided
• Easier to scale to different places in the app

Cons

• A tiny bit harder to understand
• Will require adding a new "type" to the config