[examples] Clean up examples (#8674)

Move various "examples" into snippets. Several examples that were less
than a full mechanism or robot were moved to snippets. `arcadedrive` and
`tankdrive` were removed in favor of their Gamepad variants. `hidrumble`
was removed due to being too simple. `potentiometerpid` was removed
because of low utility. `gyromecanum` replaced `mecanumdrive` for
deduplication and because very few teams run holonomic drivetrains
without gyros.

robotpyExamples/example_projects.bzl

@@ -21,10 +21,8 @@ PROJECTS = [
     "FlywheelBangBangController",
     "GettingStarted",
     "Gyro",
-    "GyroMecanum",
     "HatchbotInlined",
     "HatchbotTraditional",
-    "HidRumble",
     "HttpCamera",
     "I2CCommunication",
     "IntermediateVision",
@@ -33,7 +31,6 @@ PROJECTS = [
     "MecanumDrivePoseEstimator",
     "Mechanism2d",
     "MotorControl",
-    "PotentiometerPID",
     "QuickVision",
     "RapidReactCommandBot",
     "RomiReference",