subtask of #2265

• drop support for java8: feat(pd): integrate pd-grpc&pd-common&pd-client #2498
• upgrade Hbase 2.3+ to use Java11 runtime & drop the Java8 in server's CI https://github.com/apache/incubator-hugegraph/blob/1228dec04d38735b6f8b69244740fbd62310c2de/.github/workflows/server-ci.yml#L48
• compiler.source/target chore: minor improve for pom properties #2574
• ...