Refactor unit tests and add some

[thomasgaudelet]

What is the goal of this PR?

This PR goal is to improve unit tests. Some changes were required in other files to enable this.

What are the changes implemented in this PR?

• add unit tests for pipeline, oracle and strategies
• remove mention to "generic" in file names
• rework strategy/pipeline for easy testing. specifically, the strategy itself calls the kwargs filtering instead of the pipeline. This reduces the number of testing function required, or the complexity of the arguments, as it allows for laxer inputs to the active_learning_step function.

[alicerdv]

Nice PR! I like how neat the tests look :)

[paulmorio]

Thank you for changing the module names from their "generic-" prefixes. I think the new names sound better. Also thank you for the new tests in the oracle and pipeline as Alice says they are very clean with the new packages.

I am happy with the changes to using __call__ in strategies with the filtering step there. I have made some other small comments.

[paulmorio]

Approved, thanks for all the work, let me know when you merge so I will update the examples