Allow overriding the build rule gazelle uses for libraries/tests/binaries

# 🚀 feature request

### Relevant Rules

Gazelle Plugin

### Description

There are two issues I'm running into:
1) Some of my binaries need to use `py_image` rather than `py_binary` but gazelle can't manage deps for `py_image`.
2) I have a custom macro called `pytest_test` that I use for my tests that use pytest but Gazelle generates a `py_test` target for those files. I have to manually ignore all of those files and then manually manage the target since the `py_test` rule can properly run them.

### Describe the solution you'd like

It would be great if there was a Gazelle annotation where, for the current scope, Gazelle could be configured to use a different rule for particular target types.

### Describe alternatives you've considered

The only workaround I know of is to instruct Gazelle to ignore the files and then manage the build targets manually.