Apply isp formatter and code guidelines to source code

[bugabinga]

Elevate the code style and quality to ISP-levels.
Apply the company formatting rules globally and fix all warning by our Eclipse warning settings.

Devise a way, how to share these formatting and linting rules with potential contributors.
Create a new issue with proposed solution.
Possible Solutions:

• Recreate company policies with tools like Checkstyle or external formatters (formatter-maven-plugin, stackoverflow-discussion)
• Make Eclipse formatter and compiler settings available