svn: Add support to basic subversion authentication in SvnRepo
Some subversion servers in the wild disabled anonymous access and require to authenticate using a read only user account, typically with credentials anonymous/anonymous.
So add support for basic authentication in the subversion loader, credentials must be provided in the repository URL as with basic HTTP authentication.
Such repository has been submitted to Save Code Now service: https://anonymous@svn.cryptool.org/CrypTool1/
Migrated from D8585 (view on Phabricator)