qga: Replace 'blacklist' command line and config file options by 'block-rpcs'

qga: Replace 'blacklist' command line and config file options by 'block-rpcs'

Let's use a more appropriate wording for this command line and config
file option. The old ones are still accepted for compatibility reasons,
but marked as deprecated now so that it could be removed in a future
version of QEMU.

This change is based on earlier patches from Philippe Mathieu-Daudé,
with the idea for the new option name suggested by BALATON Zoltan.

And while we're at it, replace the "?" in the help text with "help"
since that does not have the problem of conflicting with the wildcard
character of the shells.

Message-Id: <20220727092135.302915-2-thuth@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>