LPS-49798 add column to store the original URL of an article

For articles whose authoritative origin isn't KB itself, store the
source location in this new column. The value of this source location is
expected to be any valid URL.

This can be used to identify and offer extended functionality for
articles imported from Github, Bitbucket, etc. For the moment, only
support for GitHub will be implemented.
LPS-49798 expose new field in services
LPS-49798 add field to edit form
LPS-49798 disable source location by default
LPS-49798 add ribbon when article has source URL
LPS-49798 make lang key configurable
LPS-49798 use Validator.isUrl  method for validation
LPS-49798 autogenerated
LPS-49798 match master
SOS-2418 Activities are created after the asset is created now
LPS-49499 Exclude discussion message type
LPS-48926 update solr with improved sortable field calcs
LPS-48926 SF
LPS-48926 portal compat
LPS-48926 Add constructor to fix compile error
LPS-48926 We can simply change the import since the class in compat extends the one in portal
LPS-48926 Sort
SYNC-1254 Switch classloaders once
SYNC-1254 Use token so we aren't bogged down by the slowness of encrypting a password during authentication
SYNC-1254 Ivy