Make Doxygen use PlantUML and include diagram for ILogger

• Document ns mantle_api, resolves #72 (closed)
• Add missing @brief keyword in logging related classes
• Add and use Doxygen Awesome for better docs
• Update README.md Ubuntu section and third party table
• Add PlantUML diagram for logging to docs (only if PlantUML found), partially resolves #73 (closed)
• Rm whitespace in README.md
• Fix CMake formatting for CPMAddPackage
• Fix project description in CMake

The program was tested solely for our own use cases, which might differ from yours.

Martin Stump martin.stump@mercedes-benz.com on behalf of Mercedes-Benz Tech Innovation GmbH, Provider Information