Hotfix/sangshuduo/td 11616 remove grafanaplugin submodule (#8871)

* [TD-11616]<fix>: remove grafana plugin submodule

* rename grafanaplugin/README.md

* temprory modify Jenkinsfile

* adjust pos to remove file.

Jenkinsfile

@@ -66,6 +66,7 @@ def pre_test(){
     }
     sh'''
     cd ${WKC}
+    [ -f src/connector/grafanaplugin/README.md ] && rm -f src/connector/grafanaplugin/README.md > /dev/null || echo "failed to remove grafanaplugin README.md"
     git pull >/dev/null
     git fetch origin +refs/pull/${CHANGE_ID}/merge
     git checkout -qf FETCH_HEAD
@@ -140,6 +141,7 @@ def pre_test_noinstall(){
     }
     sh'''
     cd ${WKC}
+    [ -f src/connector/grafanaplugin/README.md ] && rm -f src/connector/grafanaplugin/README.md > /dev/null || echo "failed to remove grafanaplugin README.md"
     git pull >/dev/null
     git fetch origin +refs/pull/${CHANGE_ID}/merge
     git checkout -qf FETCH_HEAD
@@ -211,11 +213,12 @@ def pre_test_mac(){
     }
     sh'''
     cd ${WKC}
+    [ -f src/connector/grafanaplugin/README.md ] && rm -f src/connector/grafanaplugin/README.md > /dev/null || echo "failed to remove grafanaplugin README.md"
     git pull >/dev/null
     git fetch origin +refs/pull/${CHANGE_ID}/merge
     git checkout -qf FETCH_HEAD
     git clean -dfx
-    git ls-files --stage   | grep 160000   | awk '{print $4}'   | xargs git rm --cached 
+    git ls-files --stage   | grep 160000   | awk '{print $4}'   | xargs git rm --cached
     git submodule update --init --recursive
     cd ${WK}
     git reset --hard HEAD~10

src/connector/grafana-pluain-is-removed-from-TDengine.md

+TDengine Grafana plugin is no more part of the TDengine repo. Please check it out from https://github.com/taosdata/grafanaplugin.