HTTP Status Errors: enrich-and-reraise

[hemidactylus]

This PR introduces a new astrapy exception in the class hierarchy, DataAPIHttpException, sibling to DataApiResponseException.

The new one represents 4xx/5xx responses from the API. Since in some cases these responses still contain useful info in the standard {"errors": [...]} format, which would be omitted in string representation of the httpx exception, now astrapy does the following:

• catches 4xx and 5xx exceptions as httpx errors
• repackages them as DataAPI exceptions, enriching them with the "error descriptors" as it does for "response exceptions" already;
• raises them.

Note that the new error class (see pictures/astrapy_exceptions.png) inherits from both DataAPIException and the httpx class: this, while not presenting relevant "diamond-type" multiple-inheritance problems, allows current flows based on catching the httpx exceptions to continue working.

[erichare]

Should this be Optional here? error_descriptors: Optional[List[DataAPIErrorDescriptor]]

Just judging by the attribute default

[toptobes]

Wouldn't [] convey the same information as Nothing? (in this context)

[hemidactylus]

Agree; and agree.
The Optional was an oversight from me, sorry and thank you for spotting this!
In line with the counterpart exception (DataAPIResponseException), there's no Optional and it is [] if nothing.

thanks!