SOLR Usage stats: prominent warning in the UI when the GeoLiteCityDB file is absent

[bram-atmire]

Is your feature request related to a problem? Please describe.

My original proposal was to make sure DSpace fails to start when GeoLiteCityDB is absent. As an alternative @tdonohue suggested to go with a UI warning instead DSpace/DSpace#12042

The underlying problem is: if it goes too long unnoticed that the GeoLiteCityDB file is absent, your repository accumulate too many stats without geo data. The geo data can be a very helpful tool to detect abusive behaviour, for example if the repository receives a lot of traffic from different IPs, but still in the same regions.

Describe the solution you'd like

If the GeoLiteCityDB file is absent, there should be a prominent warning in the UI. The warning should only be visible for admin users because for normal users it's not actionable.

Describe alternatives or workarounds you've considered

Not start DSpace at all if the file is absent.