Skip UKI test if the 'ukify' command is not available. (#129)

The `ukify` command is relatively new. So, it isn't available except on
fairly recent ditro versions. It isn't available in either Ubuntu 22.04
or AZL2, which is what our build/test pipelines use. So, skip the UKI
test if the `ukify` command isn't available.

Also, fix up the requirements section of the Quick Start guide.

Also, add the `ukify` command to the container.

Add multi-kernel support. (#109)

Remove the arbitary restrictions to allow the kernel args to be updated
when multiple kernels are installed.

In addition, remove the logic that sets `"GRUB_DISABLE_RECOVERY"` when
verity is enabled, since the logic can now handle multiple boot entries
in the grub.cfg file when a single kernel is installed.

Also, remove the requirement for `$kernelopts` to exist in the grub.cfg
file, since this logic just complicates the code.

Fix race condition when resetting partition UUIDs. (#100)

Code is missing a wait after the disks partition table is changed.

Update container base to Azure Linux 3.0. (#81)

This ensures that Image Customizer has access to the latest versions of
tools like `mkfs`.

Remove mem/cpu profiling CLI flags. (#49)

I don't believe anyone is using these flags. And removing them reduces
the clutter in the CLI's `--help`.

Add merge conflict github PR check (#10812)

Image Customizer: Add tests for Azure Linux 3.0. (#10249)

Allow the functional tests to accept both Azure Linux 2.0 and 3.0 image versions as input. Then, for the features that have different behavior based on the image version, ensure the tests for those features cover both image versions.

yasm: patch CVE-2021-33454 (3.0) (#10001)

Image Customizer: Fix container build. (#9542)

Image Customizer: Move version into separate file. (#9304)