Added new endpoint to similarity service to get descritor values given a sound_id and a list of descriptor names (will be useful for new API functionalities)
Refactored get_sound_descriptors functionality from similarity service
Added functionality to similarity service to get descriptor values given a list of sounds
Fixed normalization in new similarity service endpoints
Small bugfixes in new similarity service endpoints
More bufixes in new similarity endpoints
Merging new similarity functionalities to ApiV2