### _Why are the changes needed?_
close#3150
Expose the metadata store requests metrics:
```
kyuubi.metadata_request.total
kyuubi.metadata_request.failed
kyuubi.metadata_request.retrying
```
`total` and `failed` are cumulative, `retrying` is not.
If there are still some retrying metadata requests, we shall not restart the kyuubi server, otherwise, some metadata requests will lose.
### _How was this patch tested?_
- [x] 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#3149 from turboFei/metadata_store_metrics.
Closes#3150
1c63a64b [Fei Wang] comments
c9f55362 [Fei Wang] use meter for retrying
b68dd8e7 [Fei Wang] save
2ae533ba [Fei Wang] save
89f30ed4 [Fei Wang] save
5b491cf0 [Fei Wang] save
Authored-by: Fei Wang <fwang12@ebay.com>
Signed-off-by: Fei Wang <fwang12@ebay.com>
0089f2f0ec