Test the possibility to use SSH for authentication to github

[karimacherradi]

Feature description

Today we use Personal Access Token to authenticate when pushing nifi-templates to github, and this feature is meant to use SSH instead to authenticate to github under push.

Why is it needed?

Suggestion(s)/solution(s) [Optional]

Definition of done

Checklist (after created issue)

• [x] Added label(s)
• [ ] Added to project
• [ ] Added to milestone