[Suggestion] Add the subcommands distrobox snapshot & distrobox restore

**Is your feature request related to a problem? Please describe.**

Distrobox is a nice piece of software to not mess up my host os when playing around in a container, but it currently provides no convenient way to save me from messing up the container itself. It would be great if distrobox would allow me to create a snapshot of a container and restore it, if whatever I did ended badly. At the moment I'd have to perform the snapshoting myself and handle the removal of old snapshots myself as well.

**Describe the solution you'd like**

`distrobox snapshot` would be a new command that with the following syntax/options:

- `distrobox snapshot create $ctr --snapshot-name $name`: would create a new snapshot, the name of the snapshot would be optional
- `distrobox snapshot cleanup $ctr --keep $N`: would delete everything but the latest $N (optional parameter, defaults to something between 5 to 10) snapshots of all containers or the provided container
- `distrobox snapshot list $ctr`: list all snapshots of a container

- `distrobox rollback $ctr --snapshot $name`: restore the container $ctr to the last snapshot or the one with the provided name

**Describe alternatives you've considered**

using `podman container commit -p $ctr $name` manually and re-starting distrobox as described in the docs.

**Additional context**

A possible implementation could just store the containers in the container runtime's storage. Snapshots could be created using the id of the container, e.g. via:
`podman container commit -p $ctr distrobox-snapshot-$(podman inspect -f {{.Id}} $ctr):$(date +%s)`

which would create unique time snapshots (unless the user decides to create snapshots more frequently than once per second…).