Add sofa url column

[mostlikelee]

When attempting to use the url filter on sofa_security_release_info and sofa_unpatched_cves tables the following error is occuring:

osquery> select * from sofa_security_release_info WHERE url = 'foo';
Error: no such column: url

This change adds url columns to both tables. To note, this was not tested with an alternative sofa feed.