Decouple updates file array from predbat.py

[Meatballs1]

Very initial stage to start decoupling the update code.

I've not tested this as its a bit of a pain to do so in branch setting tags, but to get your thoughts.

[springfall2008]

Seems like a sensible approach, I can give it a try when I get time

[Meatballs1]

I will fix up the paths and see if I can find a sensible way to test. Might be worthwhile adding an optional configuration base URL in apps.yaml that can be used for testing

[Meatballs1]

I've introduced the update_override_url in the configuration which lets us point to a different fork/branch which helps a lot with testing.

I've tested with it pointing at https://raw.githubusercontent.com/Meatballs1/batpred/update_decouple/ and works for my test HAOS with Appdaemon add on and predbat manually installed. Also tested in my live dockerised appdaemon install.

I suspect there may be issues if users haven't maintained the directory structure as per the repo e.g. apps/predbat/predbat.py? You can really just dump predbat.py anywhere apps directory and it doesn't really care, but we are attempting to overwrite files based on the repo structure.

[springfall2008]

I've not forgotten this its just not made it to the top of the list yet:)

[springfall2008]

This is now done on main, in a slightly different way but the files are split up :)