block: Disable unsupported/read-only block drivers even in tools

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1957782 Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=38289604

Some of the compiled in block drivers are unsupported or supported only read-only, so we use block driver whitelists to disable them fully or forbid write access. So far, these restriction were only considered by the system emulator, but tools ignored them. As tools provide access to most, if not all, of the functionality in block drivers and we don't want to support the code, extend the restrictions to tools.

Signed-off-by: Kevin Wolf kwolf@redhat.com