Add rake task to print Geo node status
Description
Related to gitlab-org/gitlab-ee#4397 and gitlab-org/gitlab-ee#4405 it might be useful to have a rake tasks that prints the Geo node status, similar as the /admin/geo_nodes
dashboard does.
Proposal
$ gitlab-rake gitlab:geo:status
https://secondary.gitlab.example.com
------------------------------------
GitLab version: 10.3.0-rc3-ee (1727943)
Health Status: Healthy
Repositories: 1/1 (100%)
LFS objects: Not available
Attachments: 2/2 (100%)
Sync settings: Full 0 seconds (0 events)
Database replication lag: 0m
Last event ID seen from primary: 1 (less than a minute ago)
Last event ID processed by cursor: 1 (less than a minute ago)
This would make it possible to easily see if the node can be promoted to primary (see gitlab-org/gitlab-ee#4397), which might be one of the reason we'd need gitlab-org/gitlab-ee#4405.