Update scalafmt, enable import grouping

[piotrp]

Describe your changes

Four commits:

1. Renamed the pl.touk.nussknacker.engine.sttp package, because wildcard import of pl.touk.nussknacker.engine made all following sttp imports invalid due to name clash (our package was chosen over project dependency)
2. Removal of scalafix
3. Update of scalafmt
4. sbt 'scalafmtAll; scalafmtSbt'

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