Improve the interface for inputting data on the pathway to make more user friendly

[JRPearson500]

The Alpha data model was built to be as pathway-agnostic as possible - we did not want the model to rely on having a pre-defined
pathway graph (such as the Synthea approach - https://github.com/synthetichealth/synthea)..

The pathway manifests itself through the decisions made by the Intelligence Layer. Each interaction calculates a distribution over the environments, this distribution is then sampled and thus the next Environment is chosen.

One downside to this approach is that if a user does want to apply the simulation to a particular pathway, they would need to be
proficient enough at python in order to write the functionality to calculate these transition probabilities. This raises a barrier to
entry for non-technical users who wish to use the model on a particular pathway.

A way to ameliorate this issue would be to design an interface that makes it easy to define a pathway graph (and possibly the
transition probabilities) as part of the model configuration. The graph and probabilities would then need to be parsed by the model
and fed into Intelligence Layer.

An issue would still be that the probabilities of transitioning between environments would change over time, and would depend on
the Patient state - these probabilities would be unlikely to equal the initial input probabilities, so the Intelligence Layer would still need to compute the changing distributions (that is, if a realistic and somewhat flexible model was still desired).

There could be several ways to capture and encode the graphical data:

• Using a tool like neo4j or networkX
• Defining an adjacency matrix
• Each environment could hold a list of “next_environment_ids”*

Finally, to make the template language generally more robust, a tool like Jinja could be employed.