feat: add `@ape//ape/toolchain/info:*` targets

The `@ape//:*` targets are explicitly for the `exec` configuration.

This has lead to confusion when selecting a APE binary target that is needed
for the `target` configuration.

New `@ape//ape/toolchain/info` targets have been added to make the target name
explicit. A toolchain will _always_ be for the execution platform.