This is needed by the (refactored) db init mechanism, since this later uses
the main declarative base class (thus the main MetaData instance) to gather
tables to be created/dropped.
instead of converting that column as a string
As a side effect, bitbucket wise, we provided improperly the after query
parameter as a date not url encoded. This resulted in improper api response from
bitbucket's (we received from time to time the same next index as the current
one).
Related T1826
Get rid of the class based task definition in favor of decorator-based
task declarations.
Doing so, we can get rid of core/tasks.py
Task names are explicitely set to keep compatibility with task
definitions in schedulers' database.
This also add debug statements at the beginning and end of each lister
task.
