Location timing issues

I have noticed timing issues with apps that use network location. Often it makes it very slow or impossible to get a location.

Using the latest microg v0.2.17.204714 but this has been a problem - if i remember correctly - since gmscore v0.2.11, that includes UnifiedNlp 2.0-alpha6.

After some testing with my [Hellocation test app](https://github.com/ploink/Hellocation ) in combination with my [fork of Local-GSM-Backend](https://github.com/ploink/Local-GSM-Backend) I noticed the following behaviour:

1. The network location update interval cannot be shorter than 30 seconds. When an app requests updates faster than that, microG/Unifiednlp limits it to 30 seconds.
2. No location update is performed until the first 30 seconds have expired, then you get an update every 30 seconds.
3. When you close the app that requests the updates, then launch it again and restart location updates, the 30s timer is not reset. It means you have to wait anything between 0 and 30 seconds depending on the state of the location update timer.

Edit:
I did most of my testing with a previous microg version and things seem to have improved. There is still the 30s minimum, which I think is a bit slow but would need to compare with Gapps for reference. The behaviour is a little different but I can still get in a situation that it takes a while before the first location is requested. Will do some more testing.

Reproduce the timing behavior with the Hellocation test app and the Local-GSM-Backend fork named in the report, using the described UnifiedNlp and microG versions. Compare request intervals, first-update delays, and timer behavior after restarting the app; done means the observed 30-second limitations and delayed requests are explained and the intended behavior is established.

Written by the indexing model from the issue text.