[feature] Allow conan.tools.* to be extended dynamically

### What is your suggestion?

While working on RAD Studio support for Conan (In extension to the following question here: https://github.com/conan-io/conan/issues/13447), it would be really helpful if we could do the following in a fresh install of Conan:

As a third party, install a plugin package which extends the tools namespace, registers internally in Conan, gives full access to the Conan config & recipe object and allowing recipes to import conan.tools.MyPlugin functionality.

An obstacle which would have to be decided upon, would be
1) How do we handle a case where the plugin isn't installed and a user executes a recipe which depends on this plugin?
2) Making sure the design and implementation is non-destructive to existing recipe infrastructure
3) Determine the security implications this feature might have

This feature is intended to avoid having to ship a customized version of Conan when supporting third party tools and to reduce the maintenance burden in the event the Conan team decides not to include support for a given tool stack.

### Have you read the CONTRIBUTING guide?

- [X] I've read the CONTRIBUTING guide