Defender fixes

[Mygod]

Fixes #313. Can't believe we are throwing away all these data.

[Mygod]

Since gmo arrives much more frequently (and this proto doesn’t even get sent by some systems/modes) we deliberately only took missing data (name, desc, and latterly defenders)

Probably the only bit in this PR that has value is being able to ignore the proto if gyms are turned off. Which I’m not sure anyone does

@jfberry Sounds like we should have timestamp gated GMO support then. The following scenario I have observed in the wild:

1. GMO gets parsed.
2. Gym defender gets parsed after the gym flipped.
3. The scanner left the area and the gym has updated defender but outdated team/slot for a while.

I also turn off gym parsing for testing purposes (to reduce load) but probably not something people would really turn off.

[Mygod]

Speaking of time-gating GMOs, #295 merge when?