Log connection attempt errors

What does this MR do?

Log connection attempts to the API.

{"level":"info","msg":"Checking GitLab internal API availability","time":"2021-04-07T05:14:38Z"}
{"error":"failed to connect to internal Pages API: Get \"https://gitlab.jaimem.me/api/v4/internal/pages/status\": dial tcp: lookup gitlab.jaimem.me on [::1]:53: read udp [::1]:36539-\u003e[::1]:53: read: connection refused","level":"warning","msg":"attempted to connect to the API","time":"2021-04-07T05:14:38Z"}

Before this change any connection attempts made to the API would fail silently, making it very hard to debug issues like gitlab#326117 (closed) and omnibus-gitlab#4243 (closed)

TODO

• Added the Changelog (e.g. Changelog: feature) trailer to the commits that need to be included in the changelog
• Added unit tests (if required)
• Added acceptance tests (if required)
• Documentation (if required)
• Code review guidelines
• Go Style guidelines