Fix loop device search in docker when there are no loop devices before container launch

[JohnTheCoolingFan]

Description

Currently, if losetup -f has to create a new device node and is run in a docker container, the device will be created on host butt will not be available to the already running container. This PR mitigates that by running losetup -f in a container in case there are no loop devices (/dev/loop0 is checked). The container exits after executing losetup and the main build container is run after.

The MKNOD capability does not affect the issue, so it was removed.

For additional context, previous attempts at fixing: #6576 #6642 #6927 #6936

GitHub issue reference: #6568
Jira reference number AR-2132

How Has This Been Tested?

• Fresh boot on a system that doesn't have loop devices created by default
• Run a dockerized build ./compile.sh build PREFER_DOCKER=yes

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings

[efectn]

I've just tested it, the fix works very well