operator/datahub: set REQUESTS_CA_BUNDLE to include our custom CA cert bundle
We're currently seeing SSL certificate validation error when attempting
to connect to https://datahub-gms.discovery.eqiad.wmnet:30443, due to
requests
not being configured to use our custom CA cert bundle.
We add a way to set REQUESTS_CA_BUNDLE
and have it point to our custom
CA cert bundle, which should resolve the current error.
Bug: T363461