switch to official location of images (now that they exist)
introduce a different variable for the port. while here add log level.
properly fixup the templating of the urls
Simple role to install matrix-alertmanager-receiver in a docker setup.
Typically at least the following variables should be configured:
matrix_alertmanager_receiver_room_matrix_id
matrix_alertmanager_receiver_access_token
matrix_alertmanager_receiver_room_name