kits: integrate with Makefile.toml and Dockerfile

[webern]

Description

Integrate the twoliter build kit command into the Makefile.toml ecosystem. Make it possible to build a variant where the packages are built into a kit first. Possibly there should be a default mode that detects the absence of kits in the project and creates a single all-packages kit such that the Bottlerocket build still works without yet introducing Bottlerocket's kits (just an idea).

Definition of Done

When cargo make kit works. And when twoliter build kit invokes the proper Makefilte.toml prerequisites before building the kit.