install-img-deps: Require podman

This is prep for supporting bootc:
#5197

A big part of the idea with bootc is that with `bootc install`,
a container image can *install itself*:
https://github.com/containers/bootc/blob/main/docs/install.md

This will longer term replace the `ostreecontainer` verb.

However even beyond that, having podman on the (smaller netinst,
as well as bigger DVD) installer ISO will just generally be
useful for a variety of things.  For example,
one can now do e.g.:

```
%post --no-chroot
podman run ...
```

Which unblocks a lot of things!  (Some of which admittedly will
be hacks, but that's what a lot of `%post` is...)

Having a container runtime in the Live ISO is a very key
feature of the Fedora CoreOS (and RHEL CoreOS) Live ISOs,
and this brings Anaconda closer to parity too.

anaconda.spec.in

@@ -260,6 +260,8 @@ Requires: rpm-ostree >= %{rpmostreever}
 Requires: ostree
 # used by ostree command for native containers
 Requires: skopeo
+# Needed for bootc
+Requires: podman
 
 %description install-img-deps
 The anaconda-install-img-deps metapackage lists all boot.iso installation