Added RRL config options, added to server startup.

doc/knot.texi

doc/reference.texi

samples/knot.full.conf

src/knot/conf/cf-lex.l

src/knot/conf/cf-parse.y

src/knot/conf/conf.c

src/knot/conf/conf.h

src/knot/server/server.c

src/knot/server/server.h