feat: watsonx support

[tsinggggg]

Why are these changes needed?

To enhance the support of non-OpenAI models with AutoGen, adding watsonx.ai into the mix to support both IBM granite series of models and others non-IBM models hosted in watsonx.ai

Related issue number

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.
• [x] I've made sure all auto checks have passed.

[tsinggggg]

Hi @ekzhu , would you please review this? Thank you!

[tsinggggg]

Attaching updated docs screenshot from local build

[ekzhu]

Hi @tsinggggg, again thanks for your contribution and the community package. We just created a table here: https://microsoft.github.io/autogen/dev/user-guide/extensions-user-guide/index.html#list-of-community-projects for listing the community packages. Could you update your PR to make it a new entry in the table?

[tsinggggg]

Sure @ekzhu ! Just update the table

[ekzhu]

@tsinggggg thanks! I made some edit to remove the markdown page. To avoid overcrowding the docs we will be using the table only.