Configurable data quality checks

[skrawcz]

Is your feature request related to a problem? Please describe.
We should be able to configure whether we want data quality to run or not at DAG build/run time.

Describe the solution you'd like
Allowing for fine-grained control over the behavior of specific checks. This will enable the user to turn on and off certain checks at runtime.

i.e. some configuration that a user can adjust/modify via JSON or YAML or both...

Describe alternatives you've considered
N/A

Additional context
#149 prototypes some approaches here.

[elijahbenizzy]

We are moving repositories! Please see the new version of this issue at DAGWorks-Inc/hamilton#39. Also, please give us a star/update any of your internal links.

Note that everything else (slack community, pypi packages, etc...) will not change at all.