Adds: scripts to simplifying running the client and server

run_greetings_client.sh

+#!/bin/bash -e
+TARGET='Greetings Client'
+TARGET_CLASS='ex.grpc.GreetingsClient'
+TARGET_ARGS="$@"
+
+cd "$(dirname "$0")"
+mvn -q -nsu -am package -Dcheckstyle.skip=true -DskipTests
+. target/bootclasspath.properties
+echo "[INFO] Running: $TARGET ($TARGET_CLASS $TARGET_ARGS)"
+exec java "$bootclasspath" -cp "$jar" "$TARGET_CLASS" $TARGET_ARGS

run_greetings_server.sh

+#!/bin/bash -e
+TARGET='Greetings Server'
+TARGET_CLASS='ex.grpc.GreetingsServer'
+
+cd "$(dirname "$0")"
+mvn -q -nsu -am package -Dcheckstyle.skip=true -DskipTests
+. target/bootclasspath.properties
+echo "[INFO] Running: $TARGET ($TARGET_CLASS)"
+exec java "$bootclasspath" -cp "$jar" "$TARGET_CLASS"