Add API usage meter

[dsrtusr88]

Is there an existing issue for this?

• I have searched the existing open and closed issues

Is your feature request related to a problem? Please describe

On some trackers/indexers with sensitive API limits, it would be helpful to be able to see what prowlarr is currently tracking where it is with API hits. Some sites show the real-time usage and some don't, but for the ones that do, simply visiting the site and checking may also incur an API hit.

Describe the solution you'd like

In the Indexers view, a meter or gauge or indexer/trackers that have limits configured that is showing real-time or close to real-time counts/limits.

Describe alternatives you've considered

Seems like a core feature for prowlarr compared to tracking it elsewhere if all your traffic goes through prowlarr.

Anything else?

n/a