Automatic header detection tests

[muhanadz]

Added test for the new automatic column type (header) detection behavior from #67. The test will create an example CSV inclusive of the different combinations a user can use in a temp location which is passed into the new detect_headers function. The output is then checked with the expected output of said columns.

This would be a good place to start when we want to change the behavior of the automatic detection (eg column plate_id should be detected as type plate instead of the current l)

[sbesson]

Looks good. A few suggestions of extra tests to cover all the scenarios introduced in #67.

I would also propose to migrate the file under test/unit/test_automatic_header.py as it does not require a working OMERO.server/omero-test-infra infrastructure.