move VILLAS-specific config files into subdir

docker-compose.yml

etc/nginx/default.conf

etc/villas/controller/config.json

etc/villas/node/demo.conf

etc/villas/node/others/acs-inl-polito.conf

etc/villas/node/others/csu-inl.conf

etc/villas/node/others/inl-web.conf

etc/villas/node/others/inl.conf

etc/villas/node/others/snl-inl.conf

etc/villas/node/others/usc-inl.conf

etc/villas/node/websocket-demo-files.conf

etc/villas/node/websocket-demo.conf

etc/villas/node/websocket.conf

kubernetes/Makefile