Integrate descriptorgen into tng-project

[stefanbschneider]

• [x] Auto gen. sample descriptors when creating a new project
• [x] Allow to pass high-level info directly to tng-prj to genereate suitable descriptors, eg, --author. These should then be passed to tng-descriptorgen
• [x] Update tests
• [x] Update readme and example project

[stefanbschneider]

This changes the functionality and might affect the stability of tng-project. Hence, it's planned for after the release of v1.

[stefanbschneider]

Implemented in https://github.com/StefanUPB/tng-sdk-project/tree/dev/descriptorgen Will be merged after Y1 review.