Move WASC TC v2 URLs to vulndb/data

[robocoder]

To avoid duplication:

• https://github.com/vulndb/python-sdk/blob/master/vulndb/constants/wasc.py
• https://github.com/vipsoft/vulndb-php/blob/master/src/Service/ReferenceService.php#L55-L104

[andresriancho]

I agree, this should be a JSON file somewhere in our data repository and then the different libs should consume it. My proposal is to add a meta directory inside the db directory and inside add this data.

[andresriancho]

This duplication was discovered at #33 and affects python, go and php sdks.

[andresriancho]

TODO

• Find other potential sources of code duplication
• Document how they'll be implemented in data
• Move them to data and change the SDKs