Album art resizing for full screen mode

[aangelalvarez]

Album art auto-resizing for full screen mode

Summary

Adding album art resizing for default full screen mode (not available for TV mode for now):

Motivation

Sometimes the default album art size might be too small, especially on larger displays, so this new option will allow users to have a larger album art that can have a fixed size or also auto-adjust to their display size

What changed

• Adding new setting to change album art size under general settings (only full screen mode for now, not on TV mode)
• added album cover sizes: 1x (original), 1.25x, 1.5x, 1.75x, 2x, 2.5x, auto (auto scales based on window size)
• Minor cosmetic changes such as box shadows
• Adding contributing.md file

New setting

Testing on a 32 inch 4k monitor

Before these changes, matches the new 1x (default album size) mode in terms of album size

auto scale mode