Migrate/unify databases

[GuLinux]

trafficstars

Currently we use SQLite3 for storing stars data for sky map, and redis for everything else (including NGC/IC catalogs).

It would be better to unify those databases, either in only one of the two solutions, or a single alternative.

Possible alternatives:

• http://www.zodb.org/en/latest/

Note 2020-02-28

A much easier solution would be to just let AstroPhoto Plus manage redis server startup, using a non default port.