Generator of unique non-sequential short Ids

Kotlin port of shortid (the GO version), refer to their README for now.

Todo

• [x] Port everything
• [x] Basic acceptance testing (manual + unit)
• [ ] Port all (applicable) unit and integration tests
• [ ] Benchmark
• [ ] Improve documentation, adapt for Kotlin
• [ ] Publish as library
• [ ] Evaluate Kotlin multiplatform implementation