List of users on admin pages shows joined date.
see #530
fix base settings and requirements
Merge branch 'dev-senigallia' of github.com:openpolis/open_municipio into dev-senigallia
add command for removing dangling monitoring objects

run the command as follows (from the virtual env):

automatically fix the db and prints a message

print a more detailed report of the objects that are removed

don't modify the database, only print a report of monitoring objects to be deleted
fix settings
Merge branch 'dev-senigallia' of github.com:openpolis/open_municipio into dev-senigallia

Conflicts:
	open_municipio/settings.py
	requirements/main.txt
fix templates to render even in absence of municipality bodies
Merge branch 'dev-senigallia' of github.com:openpolis/open_municipio into dev-senigallia