Simplify `key_source`

[dimitri-yatsenko]

Some complex key_source properties have been introduced. They need to be simplified to improve performance. Let's review together.

[dimitri-yatsenko]

The key_source can be simplified from

 @property
    def key_source(self):
        suite2p_key_source = (
            Fluorescence
            * ActivityExtractionMethod
            * ProcessingParamSet.proj("processing_method")
            & 'processing_method = "suite2p"'
            & 'extraction_method LIKE "suite2p%"'
        )
        caiman_key_source = (
            Fluorescence
            * ActivityExtractionMethod
            * ProcessingParamSet.proj("processing_method")
            & 'processing_method = "caiman"'
            & 'extraction_method LIKE "caiman%"'
        )
        return suite2p_key_source.proj() + caiman_key_source.proj()

to equivalent

    @property
    def key_source(self):
        return (
            Fluorescence
            * ActivityExtractionMethod
            * ProcessingParamSet.proj("processing_method")
            & [
             'processing_method = "suite2p" and extraction_method LIKE "suite2p%"', 
             'processing_method = "caiman" and extraction_method LIKE "caiman%"'])

Better yet, the custom key source should be removed altogether since the make already handles the case for unknown methods and raises a NotImplementedError