OLS refactoring.

[ypriverol]

OLS is mainly used to validate the terms for each column of the SDRF. However, OLS could be unstable failing the entire validation.

The following PR does:

• [x] Check if the OLS is running.
• [x] Check if the given ontology, for example PSI-MS, is available.
• [x] All tests related with the OLSClient are updated.
• [x] Conda build tested.

[github-actions[bot]]

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