Add Azure OpenAI as a Provider for the Title Generation, Excerpt Generation and Content Resizing Features

[dkotter]

Description of the Change

This PR adds a new Provider, Azure OpenAI, and sets that up to work for the Title Generation, Excerpt Generation and Content Resizing Features.

Azure allows you to deploy your own OpenAI resource and choose which model that resource uses (so can choose something like GPT-3.5 or GPT-4). It then provides an endpoint URL and an API key that are used to make requests.

This PR adds a new Provider that accepts those arguments and then filters any requests to that endpoint. We don't set the model during those requests as that is set when the resource is deployed on the Azure side.

Closes #492

How to test the Change

To fully test things, you'll need an Azure account that has access to OpenAI (currently this has to be applied for) and then you'll need to deploy an OpenAI resource.

Once that is in place, you can then access an endpoint URL, an API key and a deployment name, which all three are needed to make successful API requests.

Title Generation.

1. Go to Tools > ClassifAI > Language Processing > Title Generation
2. Select Azure OpenAI in the provider field
3. Enter the endpoint URL, API key and deployment name
4. Save settings
5. Create/Edit a post and click the "Generate Titles" button in the sidebar panel
6. Verify that you will get the title suggestion in a popup as expected

Excerpt Generation.

1. Go to Tools > ClassifAI > Language Processing > Excerpt Generation
2. Select Azure OpenAI in the provider field
3. Enter the endpoint URL, API key and deployment name
4. Save settings
5. Create/Edit a post and click the "Generate excerpt" button in the sidebar panel
6. Verify that you will get the excerpt generated as expected

Content Resizing.

1. Go to Tools > ClassifAI > Language Processing > Content Resizing
2. Select Azure OpenAI in the provider field.
3. Enter the endpoint URL, API key and deployment name
4. Save settings
5. Create/Edit a post, add a content paragraph, and click the "Expand/Condense this text" button from the block toolbar
6. Verify that content gets resized accordingly

Changelog Entry

Added - Azure OpenAI Provider for the Title Generation, Excerpt Generation, and Content Resizing Features

Credits

Props @dkotter, @jeffpaul

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[iamdharmesh]

Thank you for adding this @dkotter. PR LGTM and it tests well. 🚀