[Docs] Add "error handling" page

[dhmlau]

Originated from: #4844

In LB3 docs, there's Running and debugging apps page. A similar version for LB4 would be useful.

Acceptance Criteria

• Review and clean up any error handling related content we have in LB4 docs
• Document how to configure http response for errors and how to report error from controller.
  • Use strong-error-handler page as a reference
  • the initial idea is to create a child page under Running and debugging apps page in LB4.

Related: #4845

[agnes512]

Closing as done