Reusing `adk run` and `adk web` with custom Runners (and other custom services)

**Is your feature request related to a problem? Please describe.**

I loved the dev specific tools (running via the cli or web) that are part of adk. However, they are good enough for simple agents. Anything that requires reliance on other custom objects (e.g. Session, artificate service, Custom/Extended Runner etc) requires one to write a custom script and thereby not utilizing the dev tools that come built in.

**Describe the solution you'd like**

While it would be difficult to specific the custom runner or service to use on CLI, refactoring the functions in
https://github.com/google/adk-python/blob/main/src/google/adk/cli/cli.py
such as `run_interactively` and `run_cli` could enable one to directly use them from their custom script (entrypoint).

**Describe alternatives you've considered**
Alternatives require duplication of code