Incorporating BAR_ALPHA_PATCH with XRDB_PATCH

[UtkarshVerma]

I wanted to dynamically change alpha value of dwm so I implemented a hacky solution for this through https://github.com/UtkarshVerma/dwm/commit/838342f42c16b78d0e2152be1f1837fbb622fb59.

I think a better, and more scalable way for this would be to handle Xresources like it is handled in st-flexipatch through the resources array. But this was fine enough for me so I did it like this.

[bakkeby]

Another alternative could be to use RGBA values in your ~/.Xresources file and add logic to handle those within dwm.

[UtkarshVerma]

The RGBA values in Xresources is really easy to implement, so I do think it would be better. This would also simplify the current logic where the scheme has to be styled twice, once for alpha and the other time for colour.