Prepare 2.0.0-beta.13 release (Part 1)

[joseharriaga]

• Refactored ModerationResult by merging ModerationCategories and ModerationCategoryScores into individual ModerationCategory properties, each with Flagged and Score properties.
• Renamed type OpenAIFileInfo to OpenAIFile and OpenAIFileInfoCollection to OpenAIFileCollection.
• Renamed type OpenAIModelInfo to OpenAIModel and OpenAIModelInfoCollection to OpenAIModelCollection.
• Renamed type Embedding to OpenAIEmbedding and EmbeddingCollection to OpenAIEmbeddingCollection.
• Renamed property ImageUrl to ImageUri and method FromImageUrl to FromImageUri in the MessageContent type.
• Renamed property ParallelToolCallsEnabled to AllowParallelToolCalls in the RunCreationOptions, ThreadRun, and ChatCompletionOptions types.
• Renamed properties PromptTokens to InputTokenCount, CompletionTokens to OutputTokenCount, and TotalTokens to TotalTokenCount in the RunTokenUsage and RunStepTokenUsage types.
• Renamed properties InputTokens to InputTokenCount and TotalTokens to TotalTokenCount in the EmbeddingTokenUsage type.
• Renamed properties MaxPromptTokens to MaxInputTokenCount and MaxCompletionTokens to MaxOutputTokenCount in the ThreadRun, RunCreationOptions, and RunIncompleteReason types.
• Removed the virtual keyword from the Pipeline property across all clients.
• Renamed the Granularities property of AudioTranscriptionOptions to TimestampGranularities.
• Changed AudioTranscriptionFormat from an enum to an "extensible enum".
• Changed AudioTranslationFormat from an enum to an "extensible enum".
• Changed GenerateImageFormat from an enum to an "extensible enum".
• Changed GeneratedImageQuality from an enum to an "extensible enum".
• Changed GeneratedImageStyle from an enum to an "extensible enum".
• Removed method overloads in AssistantClient and VectorStoreClient that take complex parameters in favor of methods that take simple string IDs.
• Updated the TokenIds property type in the TranscribedSegment type from IReadOnlyList<int> to ReadOnlyMemory<int>.
• Updated the inputs parameter type in the GenerateEmbeddings and GenerateEmbeddingsAsync methods of EmbeddingClient from IEnumerable<IEnumerable<int>> to IEnumerable<ReadOnlyMemory<int>>.
• Changed ChatMessageContentPartKind from an extensible enum to an enum.
• Changed ChatToolCallKind from an extensible enum to an enum.
• Changed ChatToolKind from an extensible enum to an enum.
• Changed OpenAIFilePurpose from an extensible enum to an enum.
• Changed OpenAIFileStatus from an extensible enum to an enum.
• Renamed OpenAIFilePurpose to FilePurpose.
• Renamed OpenAIFileStatus to FileStatus.
• Removed constructors that take string API key and options.