Feature/improve redux state creation

[cds-amal]

This PR opens up contract events for the drizzle 1.x branch and gives 1.x users an easier ramp up to connecting with drizzle's redux store, stopping short of managing middleware creation.

doc and tutorial are here (in their own branch):

1. https://github.com/trufflesuite/trufflesuite.com/tree/feature/tut-drizzle-contract-events
2. https://github.com/trufflesuite/trufflesuite.com/tree/feature/doc-drizzles-redux-store