<!--
Thanks for sending a pull request!
Here are some tips for you:
1. If this is your first time, please read our contributor guidelines: https://kyuubi.readthedocs.io/en/latest/community/contributions.html
2. If the PR is related to an issue in https://github.com/apache/incubator-kyuubi/issues, add '[KYUUBI #XXXX]' in your PR title, e.g., '[KYUUBI #XXXX] Your PR title ...'.
3. If the PR is unfinished, add '[WIP]' in your PR title, e.g., '[WIP][KYUUBI #XXXX] Your PR title ...'.
-->
### _Why are the changes needed?_
<!--
Please clarify why the changes are needed. For instance,
1. If you add a feature, you can talk about the use case of it.
2. If you fix a bug, you can clarify why it is a bug.
-->
### Description
`ConfigBuilder` currently only supports public configuration by default. In practice, there are also some configurations, which are internal configurations and do not need to be reserved for users.
refer to https://github.com/apache/incubator-kyuubi/pull/935#issuecomment-900117832
### Modification
- Add `internal` to ConfigBuilder
- Update `AllKyuubiConfiguration`
### _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/latest/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#949 from timothy65535/ky-942.
Closes#942
5d4723b3 [timothy65535] update config
b41461bb [timothy65535] [KYUUBI #942] Support for adding internal attributes to ConfigBuilder
Authored-by: timothy65535 <timothy65535@163.com>
Signed-off-by: Kent Yao <yao@apache.org>
11d1de2a0e