Some gitweb instances can have some string prefixes before the displayed
git clone URLs so ensure to strip them to properly extract URLs.
Related to swh/infra/sysadm-environment#5051.
rstrip is not a method to remove a string suffix so use another
way to extract gitweb project name.
It fixes the computation of some gitweb origin URLs.
Related to swh/infra/sysadm-environment#5050.
Depending on some instances, we have some specific heuristics, some instances:
- have summary pages which do not not list metadata_url (so some
computation happens to list git:// origins which are cloneable)
- have summary page which reference metadata_url as a multiple comma separated urls
- lists relative urls of the repository so we need to join it with the main instance url
to have a complete cloneable origins (or summary page)
- lists "down" http origins (cloning those won't work) so lists those as cloneable https
ones (when the main url is behind https).
Refs. swh/devel/swh-lister#1800
