refactor mode and states into roles and states

CMakeLists.txt

lib/client/client-handshake.c

lib/client/client-parser.c

lib/client/client.c

lib/client/ssl-client.c

lib/context.c

lib/event-libs/libev.c

lib/event-libs/libevent.c

lib/event-libs/libuv.c

lib/handshake.c

lib/header.c

lib/http2/http2.c

lib/http2/ssl-http2.c

lib/libwebsockets.c

lib/libwebsockets.h

lib/output.c

lib/pollfd.c

lib/private-libwebsockets.h

lib/server/cgi.c

lib/server/parsers.c