Merge functionality in JinjaHook.__call__ with run_dcl_hook

[robcxyz]

They overlap significantly so they should be made a little dry since this is complicated business logic and don't want to maintain it in multiple places and the objects they are acting on are the same.

[robcxyz]

I don't think this is needed. There are some fundamental differences in how these hooks are parsed since jinja hooks don't have any flow control. If anything there should be some logic to throw when flow control is inserted OR use the flow control args but that would be a little hairy. Ex foo->: {{bar(baz, if, stuff=='things'}} - This doesn't feel right.