Merge branch 'knotc_cleanup' into 'master'

Knot.files

doc/man/knot.conf.5in

doc/man/knotc.8in

doc/man/knotd.8in

doc/man_knotc.rst

doc/man_knotd.rst

doc/operation.rst

doc/reference.rst

src/Makefile.am

src/contrib/time.h

src/contrib/trim.h

src/knot/common/fdset.c

src/knot/common/log.c

src/knot/common/log.h

src/knot/common/process.c

src/knot/common/process.h

src/knot/conf/base.c

src/knot/conf/base.h

src/knot/conf/confdb.c

src/knot/conf/confdb.h