add docker-compose.mt.yml
add docker-compose.mt.yml

copied from tenantadm, needed for running new backend tests.

changelog: none

Signed-off-by: mchalczynski <3a897b56ed6fc284ae11e3e7ec3ea48d098a7178@rndity.com>

pasinskim/integration,pasinskim/integration,pasinskim/integration