Add compact mode to fit all info on smaller screens

I used to be able to see the week number, but some of the updates added new text which pushed it off screen on my phone. (At first I thought you just removed the week number, but then I looked at the code and it was still there). I assume this is a problem mainly on older devices, so I didn't want to change the default view too much, but I do need to see the week number, so I added a "compact mode" toggle under Theme settings that reduces some of the paddings and also hides the Month Note. I also moved the week number to be on the same line as the "Week of Year" text.