Add the ability to generate JUnit XML reports with a -J flag

If the -J flag is passed, generate JUnit XML reports for each check, in-line with how Java tools generate JUnit reports.
Check section numbers equate to 'root packages', checks are second-level packages, each check equates to a testsuite (mirroring Java where each test class is a testsuite) and each pass/fail of a check equates to a testcase
Time the execution of each check and include this in the report
Include properties (Prowler version, check level etc.) in-line with standard JUnit files
XML escape all strings for safety

Detect if a user has GNU coreutils installed on Mac OS X, but not as their default, switching to using gdate for date commands if so, as it has more features, including getting dates in milliseconds
Add prowler-output, junit-reports and VSCode files to .gitignore
Update README to include JUnit info, address markdownlint warnings
Remove unused arguments to jq in generateJsonAsffOutput

Fixes #537

include/outputs

@@ -16,7 +16,7 @@
 EXTENSION_CSV="csv"
 EXTENSION_JSON="json"
 EXTENSION_ASFF="asff-json"
-EXTENSION_HTML="html" # not implemented yet, use ansi2html as in documentation 
+EXTENSION_HTML="html" # not implemented yet, use ansi2html as in documentation
 OUTPUT_DATE=$(date -u +"%Y%m%d%H%M%S")
 OUTPUT_FILE_NAME=prowler-output-$OUTPUT_DATE
 
@@ -27,6 +27,9 @@ textPass(){
   fi
 
   PASS_COUNTER=$((PASS_COUNTER+1))
+  if [[ "${GENERATE_JUNIT}" -eq 1 ]]; then
+    output_junit_success "$1"
+  fi
   if [[ "${MODES[@]}" =~ "csv" || "${MODES[@]}" =~ "json" || "${MODES[@]}" =~ "json-asff" ]]; then
     if [[ $2 ]]; then
       REPREGION=$2
@@ -34,14 +37,14 @@ textPass(){
       REPREGION=$REGION
     fi
     if [[ "${MODES[@]}" =~ "csv" ]]; then
-      echo "$PROFILE${SEP}$ACCOUNT_NUM${SEP}$REPREGION${SEP}$TITLE_ID${SEP}PASS${SEP}$ITEM_SCORED${SEP}$ITEM_LEVEL${SEP}$TITLE_TEXT${SEP}$1" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_CSV 
-    fi 
+      echo "$PROFILE${SEP}$ACCOUNT_NUM${SEP}$REPREGION${SEP}$TITLE_ID${SEP}PASS${SEP}$ITEM_SCORED${SEP}$ITEM_LEVEL${SEP}$TITLE_TEXT${SEP}$1" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_CSV
+    fi
     if [[ "${MODES[@]}" =~ "json" ]]; then
-      generateJsonOutput "$1" "Pass" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_JSON 
+      generateJsonOutput "$1" "Pass" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_JSON
     fi
     if [[ "${MODES[@]}" =~ "json-asff" ]]; then
       JSON_ASFF_OUTPUT=$(generateJsonAsffOutput "$1" "PASSED" "INFORMATIONAL")
-      echo "${JSON_ASFF_OUTPUT}" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_ASFF 
+      echo "${JSON_ASFF_OUTPUT}" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_ASFF
       if [[ "${SEND_TO_SECURITY_HUB}" -eq 1 ]]; then
         sendToSecurityHub "${JSON_ASFF_OUTPUT}"
       fi
@@ -56,6 +59,9 @@ textInfo(){
     return
   fi
 
+  if [[ "${GENERATE_JUNIT}" -eq 1 ]]; then
+    output_junit_info "$1"
+  fi
   if [[ "${MODES[@]}" =~ "csv" || "${MODES[@]}" =~ "json" || "${MODES[@]}" =~ "json-asff" ]]; then
     if [[ $2 ]]; then
       REPREGION=$2
@@ -76,6 +82,9 @@ textInfo(){
 textFail(){
   FAIL_COUNTER=$((FAIL_COUNTER+1))
   EXITCODE=3
+  if [[ "${GENERATE_JUNIT}" -eq 1 ]]; then
+    output_junit_failure "$1"
+  fi
   if [[ "${MODES[@]}" =~ "csv" || "${MODES[@]}" =~ "json" || "${MODES[@]}" =~ "json-asff" ]]; then
     if [[ $2 ]]; then
       REPREGION=$2
@@ -86,7 +95,7 @@ textFail(){
       echo "$PROFILE${SEP}$ACCOUNT_NUM${SEP}$REPREGION${SEP}$TITLE_ID${SEP}FAIL${SEP}$ITEM_SCORED${SEP}$ITEM_LEVEL${SEP}$TITLE_TEXT${SEP}$1" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_CSV
     fi
     if [[ "${MODES[@]}" =~ "json" ]]; then
-      generateJsonOutput "$1" "Fail" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_JSON 
+      generateJsonOutput "$1" "Fail" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_JSON
     fi
     if [[ "${MODES[@]}" =~ "json-asff" ]]; then
       JSON_ASFF_OUTPUT=$(generateJsonAsffOutput "$1" "FAILED" "HIGH")
@@ -131,7 +140,7 @@ textTitle(){
   esac
 
   if [[ "${MODES[@]}" =~ "csv" ]]; then
-      >&2 echo "$TITLE_ID $TITLE_TEXT" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_CSV 
+      >&2 echo "$TITLE_ID $TITLE_TEXT" | tee -a $OUTPUT_FILE_NAME.$EXTENSION_CSV
   elif [[ "${MODES[@]}" =~ "json" || "${MODES[@]}" =~ "json-asff" ]]; then
     :
   else
@@ -156,7 +165,7 @@ generateJsonOutput(){
   --arg ITEM_LEVEL "$ITEM_LEVEL" \
   --arg TITLE_ID "$TITLE_ID" \
   --arg REPREGION "$REPREGION" \
-  --arg TIMESTAMP $(date -u +"%Y-%m-%dT%H:%M:%SZ") \
+  --arg TIMESTAMP "$(get_iso8601_timestamp)" \
   -n '{
     "Profile": $PROFILE,
     "Account Number": $ACCOUNT_NUM,
@@ -178,20 +187,17 @@ generateJsonAsffOutput(){
   local status=$2
   local severity=$3
   jq -M -c \
-  --arg PROFILE "$PROFILE" \
   --arg ACCOUNT_NUM "$ACCOUNT_NUM" \
   --arg TITLE_TEXT "$TITLE_TEXT" \
   --arg MESSAGE "$(echo -e "${message}" | sed -e 's/^[[:space:]]*//')" \
   --arg UNIQUE_ID "$(LC_ALL=C echo -e "${message}" | tr -cs '[:alnum:]._~-\n' '_')" \
   --arg STATUS "$status" \
   --arg SEVERITY "$severity" \
-  --arg SCORED "$ITEM_SCORED" \
-  --arg ITEM_LEVEL "$ITEM_LEVEL" \
   --arg TITLE_ID "$TITLE_ID" \
   --arg TYPE "$ASFF_TYPE" \
   --arg RESOURCE_TYPE "$ASFF_RESOURCE_TYPE" \
   --arg REPREGION "$REPREGION" \
-  --arg TIMESTAMP $(date -u +"%Y-%m-%dT%H:%M:%SZ") \
+  --arg TIMESTAMP "$(get_iso8601_timestamp)" \
   --arg PROWLER_VERSION "$PROWLER_VERSION" \
 -n '{
       "SchemaVersion": "2018-10-08",