Add MCP adapters to autogen-ext

[richard-gyiko]

Why are these changes needed?

The increasing popularity of MCP decided to migrate the community extension into the autogen-ext package.

Related issue number

Checks

• 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.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[richard-gyiko]

@microsoft-github-policy-service agree