Adding the gradle wrapper

Signed-off-by: Luca Pezzoni <luca.pezzoni@st.com>

Author: PezzoniL

gradle/wrapper/gradle-wrapper.jar

@@ -0,0 +1,6 @@
+#Thu Feb 25 17:08:34 CET 2021
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip