### _Why are the changes needed?_
Add KyuubiMySQLFrontendService stub, without Netty pipeline, part of #1334
### _How was this patch tested?_
- [x] Add some test cases that check the changes thoroughly including negative and positive cases if possible
- [ ] Add screenshots for manual tests if appropriate
- [x] [Run test](https://kyuubi.readthedocs.io/en/latest/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#1358 from pan3793/mysql-fe-stub.
Closes#1358
c091d955 [Cheng Pan] nit
61abb0f6 [Cheng Pan] Address comments
9ac70456 [Cheng Pan] Update conf
3d75acdf [Cheng Pan] nit
4a4d8a24 [Cheng Pan] Address comments
0136dd52 [Cheng Pan] nit
477474ff [Cheng Pan] KyuubiMySQLFrontendService Stub
Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>
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