Add `is_vet_tec_approved` boolean field for schools on `code_schools` endpoint about back-end

[AllenAnthes]

@kylemh Should this be a field on CodeSchool or the related Location table? For context va_accepted is currently a Location field.

[kylemh]

Code School level

[kylemh]

@AllenAnthes scoped out the commit. Work done concerning keeping up parity with that list will be done later, I'm assuming?

[AllenAnthes]

Ah, yeah. Automating the synchronization seemed more like a "nice-to-have" to me, but I'm fine with reopening this issue if you'd like to.

[kylemh]

Nah that's fine. I just worry about it getting out-of-sync.