chore(v2): gofmt format non-fields packages

This commit formats our source code using gofmt.

Because we create MRs to the fields package from labkit-spec and the generated MRs do not conform to gofmt formatting - I've elected to exclude the fields packages from this formatting pass, to avoid obfuscating future diffs.

For the same reason, I've elected to not set up automated formatting in CI / lefthook until this can be given some dedicated thought.

Ran: gofmt -w **/*.go; git restore v2/field*/