Merge pull request #8456 from rgacogne/ddist-config-check-test

dnsdist: Separate the check-config and client modes

diff --cc pdns/dnsdist-lua.cc
Simple merge

diff --cc pdns/dnsdist.cc
Simple merge

diff --cc pdns/dnsdist.hh
Simple merge

diff --cc pdns/dnsdistdist/dnsdist-lua-bindings-protobuf.cc
Simple merge

diff --cc pdns/dnsdistdist/docs/reference/config.rst
Simple merge

diff --cc regression-tests.dnsdist/test_DOH.py
Simple merge