Remove TEDCANID from Bid and TEDCNID from Tender

[georgiana-b]

Initially, we added the field xTEDCANID to Bid because we thought it would be helpful to keep the connection between the records in our DB and the original publication in TED.
We were extracting the TEDCANID from the array of publications, picking up the ID of the Contract Award Notice. However, it turns out some contracts have multiple corresponding Contract Award Notices and we have no way based on the data to understand which Contract Award Notice corresponds to which Bid.

Here is a good example where we have 4 different Contract Award Notices for the same lots:

["http://ted.europa.eu/udl?uri=TED:NOTICE:451835-2016:TEXT:EN:HTML", "http://ted.europa.eu/udl?uri=TED:NOTICE:066459-2017:TEXT:EN:HTML", "http://ted.europa.eu/udl?uri=TED:NOTICE:029190-2017:TEXT:EN:HTML", "http://ted.europa.eu/udl?uri=TED:NOTICE:451831-2016:TEXT:EN:HTML"]

Same thing happens for Tenders. According to the latest data, some tenders have multiple Contract Notices associated with them.
To continue with the example above, the parent tender has 3 Contract Notices in publications:

["http://ted.europa.eu/udl?uri=TED:NOTICE:210719-2016:TEXT:EN:HTML", "http://ted.europa.eu/udl?uri=TED:NOTICE:181988-2016:TEXT:EN:HTML", "http://ted.europa.eu/udl?uri=TED:NOTICE:210231-2016:TEXT:EN:HTML"]

Therefore we should remove both these fields since we don't tell the "full truth".
We will instead link to the tender records on OpenTender where users can see all the original TED publications.