cli: add RPM package for system-reinstall-bootc

Modified the bootc.spec file to generate a new subpackage which includes
the new system-reinstall-bootc binary.

# Try

Try out instructions:

```bash
# Make srpm
cargo xtask package-srpm

# Mock group
sudo usermod -a -G mock $(whoami)
newgrp mock

# Build RPM for RHEL
mock --rebuild -r rhel+epel-9-x86_64 --rebuild target/bootc-*.src.rpm
```

Then install the RPM (`/var/lib/mock/rhel+epel-9-x86_64/result/bootc-reinstall-2*.el9.x86_64.rpm`) on [a rhel9 gcp vm](https://console.cloud.google.com/compute/instanceTemplates/details/rhel9-dev-1?project=bifrost-devel&authuser=1&inv=1&invt=Abn-jg) instance template

contrib/packaging/bootc.spec

@@ -62,6 +62,14 @@ Provides: ostree-cli(ostree-container)
 %description
 %{summary}
 
+%package reinstall
+Summary: Utility to reinstall the current system using bootc
+Requires: podman
+# The reinstall subpackage intentionally does not require bootc, as it pulls in many unnecessary dependencies
+
+%description reinstall
+This package provides a utility to simplify reinstalling the current system to a given bootc image.
+
 %prep
 %autosetup -p1 -a1
 # Default -v vendor config doesn't support non-crates.io deps (i.e. git)
@@ -71,12 +79,17 @@ cat vendor-config.toml >> .cargo/config.toml
 rm vendor-config.toml
 
 %build
+# Build the main bootc binary
 %if 0%{?fedora} || 0%{?rhel} >= 10
     %cargo_build %{?with_rhsm:-f rhsm}
 %else
     %cargo_build %{?with_rhsm:--features rhsm}
 %endif
 
+# Build the system reinstallation CLI binary
+%global cargo_args -p system-reinstall-bootc
+%cargo_build
+
 %cargo_vendor_manifest
 # https://pagure.io/fedora-rust/rust-packaging/issue/33
 sed -i -e '/https:\/\//d' cargo-vendor.txt
@@ -110,5 +123,8 @@ make install-ostree-hooks DESTDIR=%{?buildroot}
 %{_docdir}/bootc/*
 %{_mandir}/man*/bootc*
 
+%files reinstall
+%{_bindir}/system-reinstall-bootc
+
 %changelog
 %autochangelog