Add podman provider

[nnWhisperer]

Docker socket by default exposes too much permissions. Hence, just add a podman provider, which is a drop-in replacement except that it doesn't have a socket by default(it isn't an agent unlike docker). There are issues listed here pertaining to podman, hence it has a userbase here, let's make it official.

[mrudat]

There's actually already support for podman; it's a (mostly) drop-in replacement for Docker. You just configure "docker" to use the podman command instead, and that prompts devpod to make adjustments for podman.