[Do not merge!] Feature/configure test server url and keys

[josvandervelde]

Do not merge!

This code is meant to test the staging server. The staging server will become the new test server, after which we will discontinue using the test server hardware.

Metadata

• Reference Issue: NA
• New Tests Added: No
• Documentation Updated: No
• Change Log Entry: Make url and api-keys of the test-server configurable; test the staging server as replacement for the test server.

Details

Three unittests are failing

1. test_initialize_model_from_run_nonstrict: AttributeError: module 'tests.test_runs.test_run' has no attribute '_cat_col_selector'. I think this test assumes a different state of the test-server. I don't think this failure reflects a real problem, I think the assumptions of the test are wrong. But I'm not completely sure.
2. test_learning_curve_task_1: arff.BadDataFormat: Bad @DATA instance format in line -1: TRAIN,455,0,0 -- This should be fixed by updating the evaluate.jar.
3. test_learning_curve_task_2: similar to the previous error.

[codecov-commenter]

Codecov Report

:x: Patch coverage is 75.00000% with 2 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 73.43%. Comparing base (4b1bdf4) to head (32adbba).

Files with missing lines	Patch %	Lines
openml/cli.py	0.00%	2 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1437      +/-   ##
===========================================
- Coverage    79.90%   73.43%   -6.47%     
===========================================
  Files           36       36              
  Lines         4349     4352       +3     
===========================================
- Hits          3475     3196     -279     
- Misses         874     1156     +282     

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