Consider exposing an aspect CLI plugin

We could add a third entry point next to target-determinator and driver which would contribute a command to Bazel, by implementing a https://docs.aspect.build/aspect-build/aspect-cli/5.0.1/docs/help/topics/plugins.html

If you're up for it, I could get this started. I'd like to be able to run target-determinator just with `bazel affected`.

Review the existing target-determinator and driver entry points, then read the linked Aspect CLI plugin documentation. The work is complete when a third entry point contributes a Bazel command that allows target-determinator to run through `bazel affected`.

Written by the indexing model from the issue text.