[FEATURE] Improve and unify error handling for http connections

Summary

HTTP-based Connections don't use the builtin error handling functionality of the requests module. Instead they handle just some errors selectively

What is the expected correct behavior? What was your goal?

Consider using this as a basis https://requests.readthedocs.io/en/latest/_modules/requests/models/#Response.raise_for_status

But raise a ConnectionError with context (raise from syntax) in the end, so we catch it in our error handling. see: https://docs.python.org/3/reference/simple_stmts.html#the-raise-statement

Please see #3 (closed) in etaone_internal_connectors