Update battle patterns and utils

[babit56]

Figured it would be good to PR bp_setzoom into the library instead of just having it on my own

For possible future cases I think it would be nice to make execute_pattern and add_if_not_null public so mods can use that. Moved add_if_not_null to utils, seems like a more sensible placement when its public

[babit56]

I actually have some more ideas now that I'm working on this (HostDT), specifically more args for some of the battle patterns and more utils for rvalues, so ill let this be a draft for a bit

[fuzzything44]

For possible future cases I think it would be nice to make execute_pattern and add_if_not_null public so mods can use that. Moved add_if_not_null to utils, seems like a more sensible placement when its public

I believe last time this was discussed, it was kept private intentionally because mods for the most part shouldn't need to use it; patterns they want should be available in battlepatterns instead, and if missing they should be added.

[babit56]

Seems unnecessary to me to hide it if it's just because it ideally shouldn't be needed; with how many bp's and args there are, it would surely be easier to expose the function to cover eventual edge cases?

On another note, added foreach support for LinkedList for the two relevant elements, but failed completely at implementing the interfaces like IEnumerable (so the commit message is kinda lying im realizing now) since I couldn't dereference some things and I didn't figure out how to use pointers in generics in a sensible way xD. But hey it works well enough