kits: use an rpm package for bottlerocket licenses

[webern]

Description

The script, rpm2img assumes that we are running in the Bottlerocket monorepo.
During the script execution it copies LICENSE-MIT directly from the git repo.
This is problematic because an out-of-tree build may not have these files.

Instead, we should package licenses into an RPM file during the package build step and install them from the RPM package during rpm2img.

In other words, we can no longer do this:

bottlerocket/tools/rpm2img

Line 233 in 08497fd

install -p -m 0644 /host/{COPYRIGHT,LICENSE-APACHE,LICENSE-MIT} "${ROOT_MOUNT}"/usr/share/licenses/

Definition of Done

When the build no longer relies on Bottlerocket's license files being being present during rpm2img.

id: br_licenses
epic: twoliter_exec

Related to #2669

[webern]

This is the other problematic file copy, it will be handled in a different issue:

bottlerocket/tools/rpm2img

Line 386 in 63a5005

cp /host/tools/bootconfig/empty-bootconfig.data "${PRIVATE_MOUNT}/bootconfig.data"

[webern]

This was conflated with bootconfig files, which are now handled in #3187 . I have updated this to be about the license files only.

[webern]

This may want to be part of the kits milestone since rpm2img breaks if it doesn't have access to the Bottlerocket sourcecode repository (because it wants these license files)