Move python libraries to separate options in ldns-config
Move python libraries to separate options in ldns-config

Libraries provided by ldns-config --libs differs from pkg-config --libs
ldns, when python compilation is enabled. It may bring undesired
dependencies to consuming software. Openssh is good example.

Move python libraries to --python-libs, in case it is required. Common
C build do not require python libraries at all.

NLnetLabs/ldns,NLnetLabs/ldns,NLnetLabs/ldns,NLnetLabs/ldns