modified Dockerfile source images to use smaller base images

[bradkwadsworth-mw]

Description of your changes

Recently I've been wanting to follow this method https://github.com/crossplane-contrib/function-kcl?tab=readme-ov-file#use-as-a-base-image for building custom Crossplane functions that includes schemas of the managed resources. With this workflow, a container will need to be built per composition. While I don't have an issue with this, the base image being 383MB is a little on the large side. This PR changes the base images in the Dockerfile and shrinks the golang binary using ldflags causing the new image size to be 156MB.

I have:

• Read and followed Crossplane's contribution process.
  - [ ] Added or updated unit tests for my change.

[Peefy]

Thanks for this PR.

However, if some content like git and ca-certificates in the basic image kcllang/kcl is missing, it may cause certain features such as OCI, Git Source, etc. to be unavailable. We can find some basic dependencies here https://github.com/kcl-lang/cli/blob/main/Dockerfile

Perhaps we can further reduce the size of kcllang/kcl. How do you think? cc @zong-zhe @He1pa

[bradkwadsworth-mw]

That sounds good to me I'll take a look at reducing the kcllang/kcl image. I'll modify this one to just add the ldflags to help reduce the Go binary size.

[Peefy]

Thank you! LGTM!