### _Why are the changes needed?_
- Improve log on executing init schema DDL.
- Add `IF NOT EXISTS` on `CREATE INDEX` statement.
- Fix `kyuubi.metadata.store.jdbc.url` configuration description.
- Delete SQLite files on performing `build/mvn clean`
### _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.readthedocs.io/en/master/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#4953 from pan3793/sqlite-followup.
Closes#4950
a0b44f37c [Cheng Pan] [KYUUBI #4950][FOLLOWUP] Misc improvement for usage of SQLite
Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>
f69cf9406f