Review this plugin for addition to OME org and Docker images

[manics]

The first feature is is currently done in the Docker images so should be uncontroversial. As for the others? Using YAML for OMERO.web configuration is a lot easier than a single line of dense JSON, but it's a new feature.

• Read config properties from CONFIG_omero.... environment variables.
• Read configuration from YAML/JSON: Years ago someone asked whether you could configure something like Mapr from the IDR's ansible configuration variables. Now you almost can with a bit of editting.
• Convert Jinja2 to YAML/JSON: Many of the IDR Ansible variables contain Jinja2 statements. If they are of the form {{ variable | default('x') }} this can be handled by Jinja2 since default is a built-in filter. This gets us even closer to being able to use the ansible configuration with few changes.

[joshmoore]

My first repo review:

1. From the README, it's unclear how server_set is picked up as oposed to web_set, for example.

2. Does https://github.com/manics/omero-cli-externalconfig/blob/main/.github/workflows/workflow.yml need unification with any of the templates?

3. .travis.yml can be deleted.

4. What would be the first non-docker target for use?

[manics]

1. Updated
2. See #2 though it's not currently passing
3. Deleted
4. Not sure, it's probably more useful to allow Docker to use the Ansible config than the other way around