Renamed CheeseItem to CheeseListITem
Fix imports
Minor nits

Added an example of mock differ + mock paging source style viewmodel
test, which allows testing against separator / transformation logic.

Besides refactoring a lot of imports, this PR also makes the following changes:

* Updated to targetSDK 28 and build tools 28.0.3 along with android
  gradle plugin 3.2.0
* Updated various compile and and androidTestCompile to their
  implementation version.
* Bumped Kotlin version and moved from the jre to the jdk version of
  the stb libs.
* Bumped Dagger to 2.16 which contains a fix for projects using the
  androidx namespace.
* Bumped Glide to 4.8.0 which also contains a fix for projects using
  the androidx namespace.
* Removed dexmaker in favor of mockito-android in some of the sample
  projects that used it.
* Added android.useAndroidX=true and android.enableJetifier=true to
  various gradle.properties in projects that used data binding and/or
  used libraries that expected the old namespace.

Change-Id: I46f2677e00dec5362399e2e5d719ab8b3f6e0bd6

This CL adds a new sample for the new paging library.