devel/libsoup: Massage features and options

• From PR 235207 comes a patch from mi@ to use NTLM if it's there. Unfortunately, the switch to Meson has made this run-time-option a build-time-check, so the original patch isn't directly useful. Make samba a build-time dep, so that the code is enabled; there is a run-time check if the NTLM executable is available.
• From PR 231160 comes a patch to configure different kinds of GSSAPI. That too doesn't apply with the current Meson build, but the general idea does.

Build-tested in 8 configurations (but libsoup is nice that everything
is #ifdeffed internally, so there's no plist or other visible changes)

While here, add WWW line.

PR: 235207 231160
Reported by: mi
Reported by: Sergey Akhmatov