scripts: add tool to run containerized builds

scripts: add tool to run containerized builds

Add a 'scripts/container' tool written in Python to run any command in
the source tree from within a container.  This can typically be used
to call 'make' with a compiler toolchain image to run reproducible
builds but any arbitrary command can be run too.  Only Docker and
Podman are supported in this initial version.

Add a new entry to MAINTAINERS accordingly.

Link: https://lore.kernel.org/all/affb7aff-dc9b-4263-bbd4-a7965c19ac4e@gtucker.io/
Signed-off-by: Guillaume Tucker <gtucker@gtucker.io>
Tested-by: Nicolas Schier <nsc@kernel.org>
Acked-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/9b8da20157e409e8fa3134d2101678779e157256.1769090419.git.gtucker@gtucker.io
Signed-off-by: Nathan Chancellor <nathan@kernel.org>