chore: add missing exporter api to mysql (#2373)

Author: shanshanying

addons/mysql/templates/_helpers.tpl

@@ -83,6 +83,10 @@ provider: kubeblocks
 serviceKind: mysql
 description: mysql component definition for Kubernetes
 updateStrategy: BestEffortParallel
+exporter:
+  containerName: mysql-exporter
+  scrapePath: /metrics
+  scrapePort: http-metrics
 services:
   - name: default
     roleSelector: primary
@@ -247,7 +251,7 @@ roles:
 mkdir -p {{ .Values.dataMountPath }}/{log,binlog,auditlog,temp}
 if [ -f {{ .Values.dataMountPath }}/plugin/audit_log.so ]; then
   cp {{ .Values.dataMountPath }}/plugin/audit_log.so /usr/lib64/mysql/plugin/
-fi 
+fi
 if [ -d /etc/pki/tls ]; then
   mkdir -p {{ .Values.dataMountPath }}/tls/
   cp -L /etc/pki/tls/*.pem {{ .Values.dataMountPath }}/tls/