Add Azure Embeddings Model Interface implementation

[IRooc]

This adds the Azure Embedding option so the demo in the readme works with the Azure OpenAI Api.

Example usage

 var documents = await PdfPigPdfSource.FromUriAsync(
        new Uri("https://canonburyprimaryschool.co.uk/wp-content/uploads/2016/01/Joanne-K.-Rowling-Harry-Potter-Book-1-Harry-Potter-and-the-Philosophers-Stone-EnglishOnlineClub.com_.pdf"));
 
 // This adds embedding possibility for the Azure Model  
 var embeddingModel = new AzureOpenAIModel("AZUREAPI_KEY","AZUREAPI_ENDPOINT", "EMBEDDING_DEPLOYMENT");
 var store = await InMemoryVectorStore.CreateIndexFromDocuments(embeddingModel, documents);

 var similarDocuments = await store.Store.GetSimilarDocuments(query, amount: 5);

 // use the documents in a prompt call
 var partialPrompt = similarDocuments.AsString();

I tried to mirror the OpenAI setup, and tested it succesfully on an Azure deployment.

[CLAassistant]

All committers have signed the CLA.

[HavenDV]

@all-contributors please add @IRooc for infrastructure, tests and code

[allcontributors]

@HavenDV

I've put up a pull request to add @IRooc! 🎉

[HavenDV]

Thank you very much for your contribution. Please write me your name in discord if you want and I will add you to the list of contrubutors and dev channel discussing development and immediate plans