Identity theft made simple...

Add fluent API to set high-level value generation strategy.

Provider-specific API for changing the strategy for a given property still to come. I implemented two methods; open to discussion on combining them and/or different naming idea.
Avoiding blocking on async operations by providing sync counterparts.

Fixes #374
Positive Tests for Negative Cases (adding tests for database error page)
Adding a few end-to-end tests for database error page
Also enabling shared API tests