Add missing cache headers

[dkudeki]

The cache is working, but it is not returning some expected fields in the headers like cache-control and x-torchlite-cache. Followup to #111. Would be nice to have, but not blocking any critical functionality at this point.

[jswatsch]

Currently only in dev. @sandeep-ps will check this at same time as issue #7 from arcgocd repository.

[jswatsch]

@sandeep-ps will revisit after finishing production instance