Improve Geo Admin panel for Geo DR

When we've been running through the Geo DR demo, there were some stats on the Geo admin panel that where not completely clear.

Current situation

Sync settings

It's unclear what the numbers next to "Full 🔄" mean.

IIRC 41 seconds is the time between the timestamp of the last event handled and the timestamp of the last event existing. And 1 is the number of events it's behind.

Last event ID

These numbers are hard to understand if you don't know the internals of Geo.

Health status

It shows it's healthy, but some red is in progress bars, so this gives a false feeling of everything being A-Okay.

Proposal

Geo event log progress bar

Maybe we should introduce a progress bar for the event log too:

| # events processed | # events not processed |

The problem with this, the # events processed can get quite high over time, and it becomes irrelevant how many events there were in the past. We could omit the number of processed events, but that also would not be fair, because then 1 unprocessed event would turn the whole bar red, which gives an incorrect impression.

Health status

Maybe we should show "🕗 Syncing" (just like pipeline running) when there are things not in sync.

Related issues

gitlab-org/gitlab-ee#4493