kits: somehow clean up container tags after builds complete

[webern]

Description

Because a variable number of kits (both external and local) need to be combined into a single Bottlerocket build, it may become impossible to use a single Dockerfile for all stages of the build. If this is the case then we run the risk of leaving tagged images in the local docker cache (because we need them for subsequent docker build commands). We need to figure out a way to make sure we don't endlessly add to a user's docker cache when they are doing a lot of Bottlerocket builds.

Definition of Done

When a design and implementation exists that ensures we don't leave tagged docker images behind after a Bottlerocket build involving kits.

[webern]

I don't think this is relevant with the current implementation.