Preserve MoA field from source OpenTargets

[jmillanacosta]

Is your feature request related to a problem? Please describe.
Currently the MoA gets classified into activates or inhibits leading to information loss, for instance:

• is this direct or indirect activity regulation?
• is the compound an antagonist or inverse agonist?
  

  pyBiodatafuse/src/pyBiodatafuse/annotators/opentargets.py

  Lines 532 to 535 in 5fb1765

  	drug_df["mechanismOfAction"] = drug_df["mechanismOfAction"].apply(
  	lambda x: "inhibits" if "antagonist" in x else "activates"
  	)
  	drug_df.rename(columns={"mechanismOfAction": "relation"}, inplace=True)

Describe the solution you'd like
Preserve the field to allow for more precise mappings. The current binary classification can be kept, it is useful. Some existing properties from RO could be used to model the precise MoAs in the rdf module.