insert or not insert observatory filler targets into the target database

It is still under discussion how to host observatory filler targets. Some random notes:

• Maybe just thinking about PS1 objects are okay
• Then number of objects are O(10^9).
• Community fillers will be inserted into the target table. The number of community filler targets would be O(10^6-7).

It would be a bit overwhelming to put community fillers to the target table. Instead we could create another table with a bit simplified column contents. However, it may induce some issues in the downstream (queudb, qadb, and opdb).

Further discussion with Eric and Yabe-san is needed.