Notifications when risk value has changed between low and high. (#76)

* Notifications when risk value has changed between low and high.

* Notifications when risk value has changed between low and high.
Fixed wildcard imports.

* Fixed formatting, ktlint issue.

* app foreground/background checking. Notifications are not sent when app is in background

* update comments

* initialize foreground flag as false(valid for background threads before ui starts)

* comments

* included UNDERTERMINED as a low, for initialisation

* fixed icon

* fixed tests

Co-authored-by: Jakob Möller <jakob.moeller@sap.com>