This removes all of the (now actually non-trivial) conversion logic from
the class which is actually responsible for executing the Jint engine.
This moves it all to a new service which uses chain of responsibility to
convert the result, using one of a few different mechanisms.
Of note is the handling of ExpandoObject when no specific type
information has been provided, and also the handling of enumerables,
with the exception of strings.
As well as providing a unit test which matches other persistence
provider tests (round-tripping a workflow instance), two other tests
are included here:
* When using the default DI registration extension method, this sets
up pooling of DB contexts and so a resolved context will come from
the pool.
* When using the non-pooled DI registration extension method, this
sets up EF without pooling, which is more useful in a multi-tenanted
environment.
There are also some other changes in this commit corresponding to
improving the tests. Mainly de-duplicating logic & improving names.
This refactor of integration test logic is to boost its
reusability. Moving some functionality to attributes &
customization classes means I can reuse elsewhere without
duplication.
