[prefect-docker] add cached docker build and push steps

[zzstoatzz]

this will cache the results of the existing build and push steps in memory so that if the same build or push is requested during a build step more than once, it will no-op and the result will be fetched from the cache

this is an alternative way to address #9921

i could see the argument that we should simply add caching to the existing step, but it felt like I needed a layer to handle the list / dict (non-hashable) inputs and avoid any potential weirdness associated with changing the canonical step

usage

build:
    - prefect_docker.deployments.steps.cached_build_docker_image:
        id: build-image
        requires: prefect-docker
        image_name: repo-name/image-name
        tag: dev

push:
    - prefect_docker.deployments.steps.cached_push_docker_image:
        requires: prefect-docker
        image_name: repo-name/image-name
        tag: dev
        credentials: "{{ prefect.blocks.docker-registry-credentials.dev-registry }}"

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[chrisguidry]

This is rad! Alex and I were talking with a user yesterday about this exact issue

[desertaxle]

@zzstoatzz What do you think about incorporating this behavior into the existing steps? That way users get caching with no changes needed. We could have the caching behavior be opt-out with a ignore_cache kwarg.

[zzstoatzz]

@zzstoatzz What do you think about incorporating this behavior into the existing steps? That way users get caching with no changes needed. We could have the caching behavior be opt-out with a ignore_cache kwarg.

I was debating on whether to do that - yeah I can incorporate that into the existing steps