Adding Ollama to Magentic One

[MervinPraison]

Why are these changes needed?

• Added support for a new chat completion client using the Ollama API (OllamaChatCompletionClient).
• Enhanced image handling with base64 encoding for the Ollama API.
• Updated environment-based client creation to accommodate the new Ollama client.

Related Issue Number

• No specific issue linked. You can mention an issue if applicable.

Checks

• Documentation updated to reflect new changes.
• Tested locally with Ollama

[MervinPraison]

@microsoft-github-policy-service agree

[jackgerrits]

This is great thank you! So it can be used in more places would you mind moving it to autogen-ext next to the other model clients?

[husseinmozannar]

This is awesome! As Jack mentioned, we'd love for this to be used broadly in autogen beyond magentic-one and in the AgentChat version of magentic-one

Quoting @jackgerrits : "Creating a custom model client is a matter of implementing this interface."

Happy to help on this

[ekzhu]

Possible to set up Ollama on CI action to test this?

[MervinPraison]

@jackgerrits @husseinmozannar @ekzhu Moved the Ollama Client to autogen-ext as per the suggestion

[afourney]

Looks great! Thanks for moving it to ext for broader applicability.

We should add unit tests as Eric mentioned, but I trust that this can be done in a follow up.

[jackgerrits]

I am not sure how this pull request got closed by me merging a different PR. I definitely did not mean to do this. Did you by any chance update your main branch unintentionally @MervinPraison ?

@MervinPraison are you able to create a new PR? We definitely still want this change and I would really love for you to get the credit for the commit

[MervinPraison]

Not sure why it happened like that
No problem
Sure I will create a new PR

[MervinPraison]

@jackgerrits
Created the pull requested here as per request: #4333