Quality of docstr

### Describe the feature you'd like

Currently interrogate only checks if docstrings are present without putting any value on the quality, e.g.

* Minimum summary length
* Parameters/Args are documented
* Return is documented
* Raised exceptions are documented

I understand this would be a larger piece of work due to the different docstring styles that require parsing.

### Is your feature request related to a problem?

Increase the quality of docstrings.