Lspinheiro/chore/migrate azure executor autogen ext

[lspinheiro]

Why are these changes needed?

To remove code executor dependencies from the core package.

Related issue number

Closes #3645 by removing azure-core from autogen-core dependencies and adding it to autogen-ext

Checks

• [x] I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• [x] I've added tests (if relevant) corresponding to the changes introduced in this PR.
• [ ] I've made sure all auto checks have passed.