feat: remove sample API

Feature

Summary

This MR remove the sample API we had introduced in !86 (merged) and which had only the purpose of having an endpoint for the implementation of the text styling.

Compliance to “Definition of Done”

• Unit tests passed
• Code reviewed
• Product Owner accepts the User Story

Documentation

• I updated the README (if applicable)
• I provided my functions with appropriate documentation
• I updated existing documentation

Tests

Are we able to test this new feature?

• Yes, everything can be done via unit tests.

Changelog

• I added a statement to the CHANGELOG.

Version number

• I bumped the version number in build.properties.

Closes

Closes #120 (closed)

/cc Mathias Göbel, Frank Schneider, Michelle Weidling