Handlebars replacement for contextual information

[hardyjosh]

We are using inspiration from Github for this https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/accessing-contextual-information-about-workflow-runs

There are two initial use-cases for this kind of replacement:

1. Using token addresses from the current order being deployed in the scenario bindings
2. Using token name/symbol current order being deployed in the names/descriptions of GUI fields

In both cases, the order is in context because we know the deployment, and the order is part of the deployment.

If we were accessing the scenario bindings outside of a deployment context (e.g. for making charts) then there is no order in context. This should just be an error.

I'd suggest to create a new YamlContext struct and pass it through so that when a Deployment gets its Scenario, the Deployment passes its context through to the scenario getter.