AL2023 builds only install kernel 6.1

Issue: Because the rpm names for the 6.18 kernel are "kernel6.18" instead of just "kernel", AL2023 builds will always create AMIs that boot into the 6.1 kernel. Updating the manifest to only have kernel6.18 will actually end up installing both, I think because of line 35 in Ospackages.sh in the amigen9 project. Changing that line to replace kernel with kernel6.18 causes a failure during PostBuild.sh at line 355. Replacing kernel name there with kernel6.18 will eventually let the build succeed and it will boot into 6.18.

Desired result: AL2023 builds with kernel 6.18 should either be the default, or there should be some way to specify the kernel version in the packer template for AL2023 builds.

Start by comparing line 35 of Ospackages.sh in the amigen9 project with line 355 of PostBuild.sh, then inspect the AL2023 Packer template and its kernel package manifest. Verify how kernel and kernel6.18 are selected and installed. Done means an AL2023 build uses kernel 6.18 by default or provides a working template option to select the kernel version, and the resulting AMI boots successfully.