Update LREngine.Context construction to be more fluid instead of simply adding more constructor variations

[aheber]

Is your feature request related to a problem? Please describe.
If we want to enhance the capabilities of LREngine it often means adding new settings. Passing in those settings means adding for properties to LREngine.Context. The current model adds another constructor param and cascades the existing constructors. This is untenable long-term. We need a better way to build Contexts that can be more flexible and allow us to easily add new properties.

We have a few other enhancements that will be waiting on this, anything that adds capability or configurable variability to the engine and it might behave differently for different rollups.

Describe the solution you'd like
Several options including building a factory/builder pattern, adding a Fluent API design, eschewing constructors for setting properties and just setting them directly after construction.

Find something that works well and is clean and refactor out the old ways from both the engine and anywhere it is used.