Link-Time Substitution: Native Support

### Description of the problem / feature request:

I'm using [link-time substitution](https://bramtertoolen.medium.com/link-time-substitution-c-c-test-hardware-dependent-code-91ffd4ef8687) in order to provide different implementations of the same function in different binaries (e.g. test targets, or targets with different features enabled) within the same overall build.

When working a large codebase, it's easy to either:
- Forget to depend on a target which defines an implementation of an interface, resulting in a linker error about missing functions.
- Accidentally depend on more than one implementation of an interface, resulting in an ODR violation.

I would like to be able to tag the targets which declare the interface with e.g. a `declares_symbols = [ ... ]` argument, and the targets which define it with e.g. `defines_symbols = [ ... ]` such that I get a bazel error if I try to build a target which depends on a symbol declaration which does not have exactly one definition in its dependency tree.

For example:

```python
cc_library(
name = "what_color_declaration"
hdrs = [ "what_color_declaration.h" ]
declares_symbols = [ "what_color" ]
)

cc_library(
name = "what_color_returns_blue"
srcs = [ "what_color_returns_blue.cc" ]
defines_symbols = [ "what_color" ]
)

cc_binary(
name = "binary_a"
srcs = [ "binary_a.cc" ]
// ERROR: must provide definition of `what_color`,
// declared by dep `what_color_declaration`.
deps = [ ":what_color_declaration" ]
)
```

### Feature requests: what underlying problem are you trying to solve with this feature?

I want to swap out the implementation of certain functions in different link targets (e.g. binary, test, static library) without rebuilding all dependencies.