Config and db: enable web proxy on blue. Refs #2964

* New properties: GreenMode and BlueMode
* Migration fragment from old properties
* Support blue networks in configuration templates
firewall: move squid rules after general rules. Refs #2964
db migration: fix fragment path. Refs #2964
Web UI: support blue zones. Refs #2964
squid.conf: set shutdown_lifetime to 1 seconds. Refs #2964
db defaults: default mode to manual for blue and green. Refs #2964