Multiple resolutions support

[RicArch97]

Looking at the backgrounds that currently exist, they are all 1080p.

I think it might be a good idea to create versions for the following resolutions, to make your theme widely available;

Class	Resolution
1080p	1920 x 1080
Ultrawide 1080p	2560 x 1080
1440p	2560 x 1440
Ultrawide 1440p	3440 x 1440
4K	3840 x 2160

For ultrawide, there's extra space on the sides (21:9 aspect ratio) so you'll have to shift the items accordingly.

[VandalByte]

Hi @RicArch97 The main reason for this is because of the lack of availability of hardware for testing purposes and I'm planning to release a 2K version in the next v2.0 update along with the updated 1080p version