Collect all HolochainError types in an enum

[jost-s]

Errors thrown by the client are of type HolochainError. One property is a name, which is a string. Instead it would be better to use an enum, so that there are no spelling mistakes when throwing or catching errors, and to have a central location where all possible errors are placed.

AC:

• Create HolochainErrorKind enum.
• Modify HolochainError to accept a value of the HolochainErrorKind enum instead of a name string.
• Updarte all occurrences of HolochainError.

[ThetaSinner]

I agree this would be good, but the errors from Holochain are structured to several levels of depth and seriously confusing to decode and decipher. I think we should approach this from Holochain first and simplify what you can receive as errors then look at doing this. What do you think?

[jost-s]

We can do that first, but the errors in the client here are not directly mapped to Holochain errors or even unrelated to Holochain. There are for example InvalidTokenError, WebsocketClosedError or InvalidMessageFormatError. Those I'd like to create an enum for instead of using strings literals.