preview resultsets with Preview Data extension

Putting this here to see if this is a good idea or not.

## Idea
Add a `preview` statement qualifier that can open up the result set using the Data Preview extension: https://marketplace.visualstudio.com/items?itemName=RandomFractalsInc.vscode-data-preview

example:
```sql
preview: select * from sample.employee
```
This will automatically open a new Data Preview session for the result set In order to do further sorting, slicing, and charting.

## Demo

https://github.com/codefori/vscode-db2i/assets/50843283/c5fc46d3-96f4-44b3-9fd5-19bf16ed018b

### Split by column

### Group by with metric

### Charting with custom group by, metic=avg

## TODO
- to use Data Preview, a file with an extension like `.json` must be opened. My workaround in the demo is to save the resultset as json in the Temp directory.
- remove temp json files on system disconnect
- handle error cases