Add documentation for `Set Camunda Configuration`

Since #10 we do have the new keyword `Set Camunda Configuration` - but the documentation is missing: https://robotframework-camunda-demos.gitlab.io/robotframework-camunda-mirror/latest/keywords/camundalibrary/#Set%20Camunda%20Configuration

Please add the documentation.

Start with the linked CamundaLibrary keyword documentation and locate the documentation source for the `Set Camunda Configuration` keyword. Add the missing keyword documentation, using the existing page as the reference for placement and format. Done means the generated documentation describes this keyword and is visible in the published keyword reference.

Written by the indexing model from the issue text.