Remove environment file reference from domoticz template

[Paraphraser]

New menu has moved environment variables from domoticz.env into
service.yml but the env_file reference is still present. This
causes new-menu builds to fail.

[Paraphraser]

Further to this PR, I looked through the other templates to see if there were any similar problems.

The short answer is "no" but there are some inconsistencies.

As of 2021-01-21, the .templates folder of the master branch still contains three environment files:

heimdall.env
homer.env
zigbee2mqtt_assistant.env

In turn:

• The heimdall service.yml references the environment file. None of the variables in heimdall.env have made it into service.yml.

• The homer service.yml references the environment file. None of the variables in homer.env have made it into service.yml.

• The zigbee2mqtt_assistant service.yml does not reference the environment file. Some, but not all, of the variables in the environment file have made it into service.yml, and service.yml has some variables not mentioned in the environment file. Specifically:

  • zigbee2mqtt_assistant.env contains:

     #TZ=Etc/UTC
     Z2MA_SETTINGS__MQTTSERVER=mosquitto
     #Z2MA_SETTINGS__MQTTUSERNAME=MQTTUSER
     #Z2MA_SETTINGS__MQTTPASSWORD=MQTTPASS
    

  • The service definition contains:

         - VIRTUAL_HOST=~^zigbee2mqtt_assistant\..*\.xip\.io
         - Z2MA_SETTINGS__MQTTSERVER=mosquitto
         - VIRTUAL_PORT=8880
    

Migrating homer and heimdall to inline environment variables is straightforward but I'm a bit wary of going near zigbee2mqtt_assistant because of all the commented-out variables - in the context of you saying that comments caused yaml merging problems.