REF: simplify pytables set_kind
Pass more info to the constructors and set less stuff afterwards.
Hello @jbrockmendel! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:



There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2019-12-07 15:40:20 UTC gentle ping @WillAyd.  _dtype_to_kind turns out to be useful for de-duplicating and de-state-ifying a ton of code @jbrockmendel i will look soon thanks @jbrockmendel 