* Bump up Gradle to 4.0.0 / 6.1.1

* Bump up NDK

* Bump Up SQLite

* adapt circle config

* Added submission done fragment (currently dangling in nav graph)

* fixed leftover javadoc

Architecture overview update

Fixes before Release to Open Source

Architecture overview

* fix that caused a crash for non whitelisted devices during the calculation of the active tracing time in the retention period

Adjustment Format

Formatting adjustments