Make /coverage and /docs work in new CI

[phlax]

one of the things that wasnt included in first iteration of github migration is the publishing of docs and coverage

this is necessary for /docs and /coverage commands to work on PRs

readding should not be so hard - it requires some creds and setup for the gcs_upload script

[phlax]

cc @ravenblackx

[ravenblackx]

As a local workaround in the meantime (that takes ages because it rebuilds everything in coverage mode):

bazel coverage [the set of test targets you expect to cover the thing you're checking]
(find bazel-out/k8-fastbuild/testlogs/ -name "coverage.dat" | xargs genhtml -o ~/coverage && cd ~/coverage && python3 -m http.server)

[ravenblackx]

Also probably worth noting here that the CI coverage failure is currently difficult to see the important details; doing a log search for lower than limit seems to be the only way I can get the useful info to appear, which is pretty unhelpful if you don't already know what to look for.

[phlax]

that is actually really easy - ill raise a PR now ...