Define Exception base/implementation classes

[Abhilash-Chandran]

Describe the feature you'd like

In order to clearly pass on the information from the API to the user, it is important to define the known Exceptions and Errors.
This needs to be defined as a set of abstract and concrete classes in order to be used across the API and tested.

TODO:

• Define a base Dapr exception class
• Derive a base Dapr HTTP and GRPC exception class for client implementations.