Research seminars add all agoras

[argoopjmc]

TODO: #453

PR to add code which would allow us to integrate all researchseminars series as agoras

• [ ] Add mappings for subtopics and primitive_topics : primitive_topics.txt and topics.txt
• [ ] Add code to pick up matchings : check get_topic_mapping in RSScraperRepository.py
• [ ] Add code to get and set subtopics of a talk ( not working) : check parse_create_talks in RSScraperRepository.py
• [ ] Add code to update talks ( and prevent them from being added n number of times) - there is similar code for checking whether a channel exists or not in the function which creates the agora and returns the talks.
• [ ] Add code for a script which will run as a CRON job ( not tested) : RSFetcher.py