Streamline server error deserialization when using graph core SDKs

[Ndiritu]

We currently provide different experiences across languages to handle error payloads from Graph when using only the Core SDK.
This is apparent when working with tasks (Page Iterator, Large File Upload) and Batch requests making it difficult for developers to understand the cause of failed requests.

e.g.
.NET Core SDK provides a ServiceException which stores the error payload as a string property for LFU

Java, PHP & Python currently don't expose/deserialize the error payload out of the box

We could agree to:

• allow passing custom error mappings with the option of adding convenience methods on the GraphServiceClient to create tasks while passing the generated error models under the hood.
• provide a standard Exception type for the Core SDK that we default to when no custom error mappings are present.

Previous guidance around this, worth referencing. https://github.com/microsoftgraph/msgraph-sdk-design/blob/master/content/ErrorContent.md