Refactor: Ensure usage of get_absolute_url doesn't mix in scheme and domain

[benjaoming]

In a recent bug, the root nature of the bug is the unconventional usage of Django's get_absolute_url() Model method. Despite fixing the bug, we chose to leave the broken pattern in place so the extend of the bug fix didn't go further.

This comment thread illustrates the issue and confusion: #10369 (comment)

get_absolute_url() should always return a URL that's relative to the current website, and all other usages and contracts should be deferred to a different method: We have used get_docs_url for instance when full {scheme}://{domain}{path} URLs are used on Project.

See: #10369

[benjaoming]

Since this is specifically addressing Version.get_absolute_url, we should consider returning a RedirectView in order to have support for same-site public URL.