### _Why are the changes needed?_
to close#3705 .
Add docs for JDBC authentication usage with in-memory database with config example for token validation example.
### _How was this patch tested?_
- [ ] 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.apache.org/docs/latest/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#3706 from bowenliang123/jdbc-inmem.
Closes#3705
3de9bceb [Bowen Liang] use backslash for multi-line config value
26a4d1b7 [Bowen Liang] nit
e078e985 [Bowen Liang] add JDBC auth usage with in-memory db for token validation
67624faf [liangbowen] init jdbc inmem doc
Lead-authored-by: Bowen Liang <liangbowen@gf.com.cn>
Co-authored-by: liangbowen <liangbowen@gf.com.cn>
Signed-off-by: Cheng Pan <chengpan@apache.org>
738e35100a