Add option to never ignore docstring errors

[AWhetter]

Currently the docparams extension will skip most checks if it cannot determine the type of docstring (eg Sphinx, Google, etc). This means that a docstring with just a summary line, for example, will not error. We should add a configuration variable to perform these checks regardless of whether or not the type of docstring can be determined.

pylint --version output

master

[AWhetter]

To any beginner contributors, this will likely involve adding an fallback-docstring-type (or whatever) option to the docparams checker that will get passed through to docstringify(). If a proper docstring type cannot be guessed, then the function should use the type specified in the option, and only make a Docstring as a final resort.