Clang format scripts as in MR

Add scripts to check and apply (including commit) same format sequence as in MR

Related to new section in Redmine wiki advising user to set upstream, check changes proposed by clang-format and apply them after doing hand edit where necessary

TO CHECK: The scripts right now check on hard-coded version of clang format 11.0.0

scripts/check-apply-format-changes.sh

+#!/bin/bash
+
+if [[ $# -ne 1 ]]; then
+  echo "Missing argument! please call this script with either the check or apply argument:"
+  echo "./scripts/check-apply-format-changes.sh check"
+  echo "./scripts/check-apply-format-changes.sh apply"
+  exit -1
+fi
+
+if [[ -z $GIT_CLANG_FORMAT_BIN || -z $CLANG_FORMAT_BIN ]]; then
+  echo "Error: GIT_CLANG_FORMAT_BIN or CLANG_FORMAT_BIN not defined"
+  echo "=> Please follow the instruction at https://redmine.cbm.gsi.de/projects/cbmroot/wiki/Clang-format"
+  exit -1
+fi
+
+# Check clang-format version
+VERSION=$($CLANG_FORMAT_BIN --version)
+if [[ "$VERSION" != *"11.0.0"* ]]; then
+  echo "Error: CLANG_FORMAT_BIN version not matching the standard cbmroot one (used in the MR test chain)"
+  echo "11.0.0 vs " $VERSION
+  echo "=> Please follow the instruction at https://redmine.cbm.gsi.de/projects/cbmroot/wiki/Clang-format"
+  exit -1
+fi
+
+if [ -z $UPSTREAM ]; then
+  UPSTREAM=$(git remote -v | grep git.cbm.gsi.de[:/]computing/cbmroot | cut -f1 | uniq)
+  if [ -z $UPSTREAM ]; then
+    echo "Error: Name of upstream repository not provided and not found by automatic means"
+    echo 'Please provide if by checking your remotes with "git remote -v" and exporting UPSTREAM'
+    exit -1
+  fi
+fi
+echo "Upstream name is :" $UPSTREAM
+
+BASE_COMMIT=$UPSTREAM/master
+CHANGED_FILES=$(git diff --name-only $BASE_COMMIT | grep -E '.*\.(h|hpp|c|C|cpp|cxx|tpl)$' | grep -viE '.*LinkDef.h$')
+
+case $1 in
+  check)
+    echo "Checking if there are format changes required"
+    git fetch $UPSTREAM
+    $GIT_CLANG_FORMAT_BIN --commit $BASE_COMMIT --diff $CHANGED_FILES --extensions h,hpp,c,C,cpp,cxx,tpl
+    ;;
+
+  apply)
+    echo "Applying required format changes"
+    $GIT_CLANG_FORMAT_BIN --verbose --commit $BASE_COMMIT $CHANGED_FILES --extensions h,hpp,c,C,cpp,cxx,tpl
+    git status
+    echo "Next step: git add "$CHANGED_FILES
+    echo 'Then     : git commit -m"Apply clang-format"'
+    ;;
+
+  *)
+    echo "Invalid argument! please call this script with either the check or apply argument:"
+    echo "./scripts/check-apply-format-changes.sh check"
+    echo "./scripts/check-apply-format-changes.sh apply"
+    exit -1
+    ;;
+esac