Move all data test reference content to "For data tests"

### Contributions

- [x] I have read the contribution docs, and understand what's expected of me.

### Link to the page on docs.getdbt.com requiring updates

https://docs.getdbt.com/reference/data-test-configs

### What part(s) of the page would you like to see updated?

Move the [data test property](https://docs.getdbt.com/reference/resource-properties/data-tests) page to join the "[For data test](https://docs.getdbt.com/reference/data-test-configs)" section.

### Additional information

From @graciegoheen
> thoughts on combining [this](https://docs.getdbt.com/reference/resource-properties/data-tests) docs reference page for data tests and [this](https://docs.getdbt.com/reference/data-test-configs) docs reference page for data test configurations?
i find it a bit odd that data_tests docs is nested under “properties” when there is a section called “for data tests”