We put the whole of this document into the system manual, though
technically a few parts of it apply to qemu-img or qemu-nbd which are
otherwise documented in tools/.

We only make formatting fixes, except for one use of 'appendix' which
we change to 'section' because this isn't an appendix in the Sphinx
manual.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20200228153619.9906-19-peter.maydell@linaro.org
Message-id: 20200226113034.6741-18-pbonzini@redhat.com