* Deadman notification: strings, onetimeworker, time calculation and unit tests

* Periodic deadman notification worker added

* Deadman notification refactor

* Deadman notification refactor
New tests

* Worker refactored to new DI

* Test boilerplate added

* Additional tests

* Clean up

* Added mock providers for deadman notification workers

* Comments and code clean up

* Test clean up

* Schedule work from CoronaWarnApplication

* Variable naming fix

* Switch to foreground state

* Formatting

* Formatting

* Inject Notification Manager Compat

* Change WorkManager initialization, make it impossible to inject the instance without it being initialized.

Co-authored-by: harambasicluka <64483219+harambasicluka@users.noreply.github.com>
Co-authored-by: Matthias Urhahn <matthias.urhahn@sap.com>