docs/install: Also document using --rm

[cgwalters]

There's no reason to leak these containers by default.

[vrothberg]

LGTM

Did you consider integrating this call into bootc itself? Maybe this could be hidden behind a flag? Maybe something like bootc --image=<image> ARGS... which would be translated into podman run $flags-that-I-keep-forgetting <image> ARGS...

[cgwalters]

That'd require the person invoking the tool to already have bootc in their $PATH which will be true for some but not others. There's no bootc in e.g. the current RHEL 9 AMI. Also if I want to script an in-place reprovision, I'll actually need to encode the command into something like an Ansible/Terraform config which generates my cloud-init configuration (potentially even doing dev work on a Mac or Windows env).