feat: Add ability to squash builds

[gmpinder]

Trying to support an older version of buildah and podman proved too difficult. Instead we'll just run the build inside a container. From my own testing with the squash builds, when you run buildah/podman inside a container, the builds can be incredibly slow with all the multi-stages and mounts on the RUN instructions. However, activating squash (--layers=false) the build runs just as fast as normal. Activating the squash feature will by default not make use of any cache abilities.

[fiftydinar]

Can some code get reused from building cached image, instead of having to update CLI version twice & having 2 same codes for determining recipe?

[gmpinder]

Can some code get reused from building cached image, instead of having to update CLI version twice & having 2 same codes for determining recipe?

Good idea. I'll work on that