Fixed #22058 -- Refactored handler and created a generic mechanism to deal with server/client errors.

**What is done**:

- Refactored handlers into generic ones.
- Deprecated original default views.
- Added generic views.

**Improvements Required**:
- Docs build have several warnings due to removing original handlers.
- A writeup for new views.

**Suggestions**:
- We could add two generic exceptions also: `HttpClientException` and `HttpServerException` to add onto the functionality.

`content_type` seems like an extra detail that we don't really need for these tests (along with the corresponding assertions)