Add script for Coverity Scan

.dd4hep-ci.d/coverity_scan.sh

+#!/bin/bash
+
+export COMPILER_TYPE="gcc"
+
+source /Package/.dd4hep-ci.d/init_x86_64.sh
+
+cd /Package
+mkdir build
+cd build
+cmake -D DD4HEP_USE_GEANT4=ON -D DD4HEP_USE_BOOST=ON -DBoost_NO_BOOST_CMAKE=ON -D DD4HEP_USE_LCIO=ON -D BUILD_TESTING=ON  -D Geant4_DIR=$G4INSTALL/lib64/Geant4-10.2.2 -D DD4HEP_USE_CXX11=ON -DCMAKE_BUILD_TYPE=Release -DROOT_DIR=$ROOTSYS -DCMAKE_CXX_FLAGS="-fdiagnostics-color=always" .. && \
+export PATH=/Package/cov-analysis-linux64/bin:$PATH && \
+cov-build --dir cov-int make -j2 && \
+tar czvf myproject.tgz cov-int