Add support for text embeddings

[vasinov]

We need a Griptape-native way to work with text embeddings and vector databases in order to support the following requested functionality:

• Enable LLMs to access processed text data in vector databases via Griptape tools.
• Help users generate text embeddings for their existing text and use it in Griptape tools.

Here is a general outline of proposed embeddings components and improvements

• Generic BaseEmbeddingDriver and OpenAiEmbeddingDriver.
• Update TextDocument to store and lazily generate embeddings.
• Generic BaseVectorStorageDriver abstraction to provide a generic way to load and store embeddings.
• PineconeVectorStorageDriver to be the first vector driver in order to support the most popular vector DB.