Besides the relatively recent update to libsoup-3, this has not seen
much development and lacks several features. There does not seem to be
any advantage over using the curl plugin. So just remove it to reduce
the maintenance burden.
This has not seen any significant changes for years. So it lacks support
for modern algorithms and would require quite some work for an overhaul.
Given that we support several other crypto backends, let's just remove
this to reduce the maintenance burden.
The test scenarios and other references are also removed.
Tobias Brunner