Add instance segmentation mask support

[aranega]

Relates to

Description

This PR introduces the notion of InstanceSegmentationMask for the DB ingestion. We followed the recommendation and steps listed in this link.

The following screenshot and JSON fragment shows the resulting instance segmentation mask included in neuroglancer, and the related state configuration.

{
	"layers": {
      "type": "segmentation",
      "source": {
        "url": "precomputed://http://localhost:9000/10442/24aug01b_Position_33_5/Reconstructions/VoxelSpacing5.006/NeuroglancerPrecompute/100-intracellular_anatomical_structure-1.0_instancesegmentationmask",
        "transform": {
          "outputDimensions": {
            "x": [
              5.006e-10,
              "m"
            ],
            "y": [
              5.006e-10,
              "m"
            ],
            "z": [
              5.006e-10,
              "m"
            ]
          },
          "inputDimensions": {
            "x": [
              5.006e-10,
              "m"
            ],
            "y": [
              5.006e-10,
              "m"
            ],
            "z": [
              5.006e-10,
              "m"
            ]
          }
        },
        "subsources": {
          "default": true,
          "mesh": true
        },
        "enableDefaultSubsources": false
      },
      "pick": false,
      "tab": "rendering",
      "selectedAlpha": 1,
      "hoverHighlight": false,
      "meshRenderScale": 2,
      "segments": [
        "1",
        "2",
        "3",
        "4",
        "5"
      ],
      "segmentColors": {
        "1": "#ff00ff",
        "2": "#800000",
        "3": "#1063ff",
        "4": "#f7bb01",
        "5": "#36fad8"
      },
      "name": "100 intracellular anatomical structure instancesegmentation"
    }
}

Note

As note/question, we unsure about the tests we introduced for the db-ingestion. We followed the same pattern than the one for annotations in general we modified:

• foo-1.0.json for 30001/RUN1 to introduce new files;
• conftest.py to align the file_size with the new size of foo-1.0.json;
• test_db_annotation.py to add the injected files as part of the assertions.

The tests are passing, but we are not sure if we need to tests the db-import differently or add something else.

[kaloster]

@aranega the test coverage here looks good and comprehensive to me and follows the existing pattern 🚀

[daniel-ji]

@uermel I've gone ahead and resolved merge conflict issues and opened a PR (#602) with those fixes (I can't actually resolve merge conflicts on this branch since I have no write permissions), not sure if MetaCell is still working on this, if not, I'm happy to carry this to the finish line; if MetaCell is still working on this, I can move my comments from the #602 PR here and also PR my changes into the MetaCell branch. The largest issue I see is no source/standardized/shared S3 validation of the instance segmentation mask files. If this out of scope of the PR, happy to re-review and approve. I also have left more detailed comments in the PR at #602. Thanks!