Code cleanup for future FtcRobot controller

[thoughtless42]

We have a script that takes care of these issues, but thought the larger ftc community could benefit from this request. 1.)FIRST-Tech-Challenge/FtcRobotController/FtcRobotController/build.gradle compileOptions { sourceCompatibility JavaVersion.VERSION_1_7 targetCompatibility JavaVersion.VERSION_1_7 }

should these be JavaVersion.VERSION_1_8 to match build.common.gradle ?

2.) FtcRobotController/FtcRobotController/src/main/assets/ this folder should be removed, it adds undue size to the robot controller apk and does not add value. These historic files can be added to a new repository along with the pdf target files; split into separate dependencies like the last 2 seasons within build.dependencies.gradle dependencies { implementation 'org.firstinspires.ftc:gameAssets-PowerPlay:1.0.0' }

3.) FtcRobotController/FtcRobotController/src/main/java/org/firstinspires/ftc/robotcontroller/internal/FtcOpModeRegister.java remove import org.firstinspires.ftc.robotcontroller.external.samples.ConceptNullOp; this import is not used and puts an undefined dependency on the external/samplesfolder on FtcOpModeRegister.java