Split types.go into several files

Created by: eseliger

Review commit-by-commit. It basically reorganizes the huge file into several smaller ones. I initially also wanted to add tests, since the coverage is quite low, but turns out thats not correct, the coverage is just not captured because it's covered across package borders. Turns out what I would have tested already is, and the main untested parts are some events and the metadata update logic, I feel like adding tests here would just be for the sake of completeness, though, so unless you veto, I would leave that work for maybe later, if we feel like doing it then.

Closes #13174

Created by: codecov[bot]

Codecov Report

Merging #14188 into main will decrease coverage by 0.00%. The diff coverage is 26.79%.

@@            Coverage Diff             @@
##             main   #14188      +/-   ##
==========================================
- Coverage   51.48%   51.47%   -0.01%     
==========================================
  Files        1514     1521       +7     
  Lines       77132    77131       -1     
  Branches     6942     6942              
==========================================
- Hits        39712    39705       -7     
- Misses      33837    33841       +4     
- Partials     3583     3585       +2     

Flag	Coverage Δ		*Carryforward flag
#go	51.74% <26.79%> (-0.02%)
#integration	29.19% <ø> (ø)		Carriedforward from 51588b6
#storybook	18.32% <ø> (ø)		Carriedforward from 51588b6
#typescript	50.84% <ø> (ø)		Carriedforward from 51588b6
#unit	34.04% <ø> (ø)		Carriedforward from 51588b6

*This pull request uses carry forward flags. Click here to find out more.

Impacted Files	Coverage Δ
internal/campaigns/campaign.go	0.00% <0.00%> (ø)
internal/campaigns/changeset_event.go	0.00% <0.00%> (ø)
internal/campaigns/changeset_spec_description.go	0.00% <0.00%> (ø)
internal/campaigns/campaign_spec.go	16.66% <16.66%> (ø)
internal/campaigns/changeset_spec.go	18.18% <18.18%> (ø)
internal/campaigns/util.go	45.45% <45.45%> (ø)
internal/campaigns/changeset.go	54.66% <54.66%> (ø)
internal/campaigns/syncer.go	100.00% <100.00%> (ø)
.../internal/codeintel/resolvers/graphql/locations.go	79.38% <0.00%> (-6.19%)
cmd/frontend/graphqlbackend/zoekt.go	75.91% <0.00%> (-0.29%)
... and 771 more