[GOCA] Add typed and exportable errors for not found and multiple resources found

[dmvolod]

Description
As golang developer I would like to easily catch situations when resource not found or multiple resources with that name are occuring.
But in current code, there are no specific error types are defined.

Use case
Easy catching and unwrapping specific errors which emits in all ByName() functions.

Interface Changes
Golang API

Additional Context
Will provide this fix soon by myself. It wolud be nice to target this enhance,ent to the latest 6.x release if possible.

Progress Status

• Code committed
• Testing - QA
• Documentation (Release notes - resolved issues, compatibility, known issues)