Last non-technical editor of the scenario in the API response

[mgoworko]

Describe your changes

Return (optionally) additional information from the processes API - about the last non-technical edit of the scenario.

There are multiple cases, where Nu scenarios are updated automatically - that includes migrations and automatic updates. As a result, the last user who edited the scenario is very often "Nussknacker".

This change introduces additional, optional, fields in the API response, with information about last non-technical user who edited the scenario. Only backend is modified, the additional information is not used on the FE yet.

Checklist before merge

• Related issue ID is placed at the beginning of PR title in [brackets] (can be GH issue or Nu Jira issue)
• Code is cleaned from temporary changes and commented out lines
• Parts of the code that are not easy to understand are documented in the code
• Changes are covered by automated tests
• Showcase in dev-application.conf added to demonstrate the feature
• Documentation added or updated
• Added entry in Changelog.md describing the change from the perspective of a public distribution user
• Added MigrationGuide.md entry in the appropriate subcategory if introducing a breaking change
• Verify that PR will be squashed during merge