relative pfade für automatisches ssh https

Closes #4

See merge request !5

App-Server ist mit Datei Konfigurierbar

See merge request !4

Feature/build/android gradle plugin 3.5.3

See merge request !3

Android gradle Plugin 3.4.2

See merge request !2

Update gradle wrapper to version 5.5.1
Sync OpenASiST4Android with merge commit of branch '25-stundenplan-anzeige-vorlesungstyp'
Reorganize ASiST core imports
Google service import located in the bottom of the OpenASiST build file
Use google repository import function instead of maven repository include
Use SDK version 28
Update target SDK to version 26
Enable AndroidX migration
Build do not use key store file

Fix link to licence file

See merge request !1