### _Why are the changes needed?_
The changes are needed to make doc page clearer and a bit nicer, and reflect latest changes in the chart.
### _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
- [ ] [Run test](https://kyuubi.readthedocs.io/en/master/develop_tools/testing.html#running-tests) locally before make a pull request
This patch had conflicts when merged, resolved by
Committer: Cheng Pan <chengpan@apache.org>
Closes#4314 from dnskr/update_helm_chart_doc_page.
Closes#4314
d7c18fd53 [dnskr] [DOCS][HELM] Refine helm chart docs
Authored-by: dnskr <dnskrv88@gmail.com>
Signed-off-by: Cheng Pan <chengpan@apache.org>