adding Notifications and DataManagement labs

labs/Lab5_DatamangementLab/.gitignore

labs/Lab5_DatamangementLab/.idea/.name

labs/Lab5_DatamangementLab/.idea/codeStyles/Project.xml

...ab5_DatamangementLab/.idea/codeStyles/codeStyleConfig.xml

labs/Lab5_DatamangementLab/.idea/gradle.xml

labs/Lab5_DatamangementLab/.idea/jarRepositories.xml

labs/Lab5_DatamangementLab/.idea/misc.xml

labs/Lab5_DatamangementLab/.idea/runConfigurations.xml

labs/Lab5_DatamangementLab/.idea/vcs.xml

labs/Lab5_DatamangementLab/DataManagementLab.mp4

labs/Lab5_DatamangementLab/DataManagementLab.pdf

labs/Lab5_DatamangementLab/app/.gitignore

labs/Lab5_DatamangementLab/app/build.gradle

labs/Lab5_DatamangementLab/app/proguard-rules.pro

...androidTest/java/course/labs/lab5_datalab/ExternalTest.kt

...droidTest/java/course/labs/lab5_datalab/SharedPrefTest.kt

labs/Lab5_DatamangementLab/app/src/main/AndroidManifest.xml

...ab/app/src/main/java/course/labs/lab5_datalab/External.kt

...pp/src/main/java/course/labs/lab5_datalab/MainActivity.kt

.../app/src/main/res/drawable-v24/ic_launcher_foreground.xml