Added some text size options people asked for

[IanEatsBabies]

https://github.com/wassy92x/lovelace-digital-clock/issues/23

People wanted some options to size the text on the clock, I ended up forking and implementing, here's (I hope, first time github pulling n stuff) a pull request to merge into your project, should you approve.

[dermorpher]

Sorry, but how do i install your version? thx a lot!