Api get roi

[will-moore]

What this PR does

This adds support for GET and DELETE of a single ROI at /api/v0/m/rois/{ID}/
I found this missing functionality to be useful in recent iviewer work on ROIs.

Testing this PR

1. Go to /api/v0/m/rois/{ID}/ with an ROI ID and you should get ROI JSON with shapes loaded
2. Tests should be passing

[mtbc]

https://ci.openmicroscopy.org/job/OMERO-DEV-merge-integration-Python27/lastCompletedBuild/testReport/OmeroWeb.test.integration.test_api_rois/TestContainers/ looks good and manual testing gives me the expected ROIs as JSON.

[joshmoore]

@will-moore : can you say anything to how you see this endpoint possibly evolving? i.e. will more be added and if so will it break the API?

[jburel]

@will-moore ping in case you missed the question?

[will-moore]

Sorry - This was just a small missing feature I wanted to add. It doesn't break any of the existing API. I'm not planning to add anything more just now. Of course, there's a lot of places where we could expand on the JSON api, e.g. #5315, #5487, annotations, shapes, search, rendering settings, updates & deletes etc

[joshmoore]

Assuming all the simple get/delete endpoints match, then 👍 merging.