Build librdkafka with gssapi support for pip package, fixes #325

[timkpaine]

As title, builds librdkafka with GSSAPI support via cyrus-sasl, enabling this feature for our pip packages (currently this only works on our conda packages).

No windows support for now as vcpkg krb5 does not support our static build, will make a separate ticket to track

xref: https://github.com/microsoft/vcpkg/issues/40320