Include admin page definitions for models and fix bugs

These changes include all the admin.py changes necessary to show all the models in admin page. This MR also fixes a bug related with picking a job that is not assigned to the worker, and a possible deadlock when the number of workers is high.

MR !3 (merged) includes more changes, you can review this or !3 (merged).

VERSIONS

DB_IMAGE_NAME: "cauldronio/database:0.1.1"
WEB_IMAGE_NAME: "cauldronio/webserver:1.0.0"
WORKER_IMAGE_NAME: "cauldronio/poolsched:1.0.0"
ODFE_CONFIG_IMAGE_NAME: "cauldronio/odfe-config:0.1.15"
PA_TO_ES_IMAGE_NAME: "cauldronio/pa-to-es:0.1.2"
ELASTIC_IMAGE_NAME: "amazon/opendistro-for-elasticsearch:1.8.0"
KIBANA_IMAGE_NAME: "amazon/opendistro-for-elasticsearch-kibana:1.8.0"
SYSLOG_IMAGE_NAME: "cauldronio/syslog-ng:0.6"
MATOMO_IMAGE_NAME: "matomo:3"

REPOSITORIES CHANGED

• Deployment: cauldron-deployment!90 (merged)
• Web: cauldron-web!185 (merged)
• Worker: -