Get all the jobs for a given timestamp: slow, because not using the parse_timestapms index, but doing a seq scan
Finding jobs is now using the index.
For debugging purposes the function to get the jobs at a certain time
is converted from sql into pgsql. We can now add some RAISE statements etc if needed.
Parsing the timestamps now works.

The schedule column currently is text, we will probably need to change this into a DOMAIN for clarity.