Add XML based vtk datatype

[tStehling]

Added the datatype VTK Unstructured Grid / VTU so the VTU files can be processed by Galaxy tools.
Also added test data for the sniff method.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. Use a tool that processes VTU files

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[bgruening]

Is it possible to reduce the test data size to a bare minimum?

Thanks a lot @tStehling!

[bernt-matthias]

Thanks @tStehling. Really good start.

The implementation might fit better to https://github.com/galaxyproject/galaxy/blob/dev/lib/galaxy/datatypes/constructive_solid_geometry.py

[bernt-matthias]

Can you remove this TODO:

galaxy/lib/galaxy/datatypes/constructive_solid_geometry.py

Line 195 in 8f22c93

TODO: only legacy formats are currently supported and support for XML formats

Would be great if we would have also tests for set_meta. Maybe analogous to:

galaxy/test/unit/data/datatypes/test_qiime2.py

Line 66 in 8f22c93

def test_qzv_set_meta():

The datatype needs to be added here as well https://github.com/galaxyproject/galaxy/blob/8f22c937894c718f513401279a55bddf40ba79cb/lib/galaxy/config/sample/datatypes_conf.xml.sample

[bernt-matthias]

I think a unit test along the lines of

galaxy/test/unit/data/datatypes/test_qiime2.py

Line 21 in e74ff84

def test_qza_set_meta():

would be great.