[KYUUBI #3705] Add docs for JDBC authentication usage with in-memory …

…database

### _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

3de9bce [Bowen Liang] use backslash for multi-line config value
26a4d1b [Bowen Liang] nit
e078e98 [Bowen Liang] add JDBC auth usage with in-memory db for token validation
67624fa [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>
(cherry picked from commit 738e351)
Signed-off-by: Cheng Pan <chengpan@apache.org>

docs/security/jdbc.md

@@ -46,4 +46,23 @@ kyuubi.authentication.jdbc.url = jdbc:mysql://127.0.0.1:3306/auth_db
 kyuubi.authentication.jdbc.user = bowenliang123
 kyuubi.authentication.jdbc.password = bowenliang123@kyuubi
 kyuubi.authentication.jdbc.query = SELECT 1 FROM auth_table WHERE user=${user} AND passwd=MD5(CONCAT(salt,${password}))
-```
+```
+
+## Authentication with In-memory Database
+
+Used with auto created in-memory database, JDBC authentication could be applied for token validation without starting up a dedicated database service or setting up a custom plugin. 
+
+Consider authentication for a pair of a username and a token which contacted with an `expire_time` in 'yyyyMMddHHmm' format and a MD5 signature generated with sequence of `expire_time`, `username` and a secret key. With the following example, an H2 in-memory database will be auto crated with Kyuubi Server and used for authentication with its system function `HASH` and checking token expire time with `NOW()`.
+
+```properties
+kyuubi.authentication=JDBC
+kyuubi.authentication.jdbc.driver.class = org.h2.Driver
+kyuubi.authentication.jdbc.url = jdbc:h2:mem:
+kyuubi.authentication.jdbc.user = no_user
+kyuubi.authentication.jdbc.query = SELECT 1 FROM ( \
+  SELECT ${user} as username, 'secret_key' as secret_key, \
+  SUBSTRING(${password}, 0, 12) as expire_time, \
+  SUBSTRING(${password}, 13) as signed \
+  ) WHERE signed = RAWTOHEX(HASH('MD5', CONCAT(secret_key, username, expire_time))) \
+  AND PARSEDATETIME(expire_time,'yyyyMMddHHmm') > NOW()
+```