core (memory/sqla_mapping): fix some technical debt: a first Alembic revision file is joined to migrate existing databases to new mapping. This patch: - set `nullable=False` in various places - drop legacy `message_types` table, and use `Enum` instead - use naming convention, and get rid of anonymous constraint (this is the main reason why the revision file is so long)

#!/bin/sh

eval $(dbus-launch --sh-syntax)

# default, backend is launched in foreground
if [ $# -eq 0 ]
then
	exec libervia-backend fg
fi

# backend is launched with an explicit subcommand
if [ $1 = fg -o $1 = bg -o $1 = debug -o $1 = stop -o $1 = status ]
then
	exec libervia-backend "$@"
fi

# a whole command is specified
libervia-backend bg
exec "$@"