Reduce queries to 1 for datastore config
Rename number_of_plates to number_of_detectors
Undo move of import Configuration

Placing it at the top of the file does not work for some reason
Reduce number of queries for Nagios config

From ~25xN to 2xN+N(mpv)
Reuse a query and use select_related on some others
Most time consuming was finding the number of detectors
Now only done for stations that have mpv monitoring enabled
Time consumption for looking in Configurations will become a problem
At least the latest configs should be easily accessible