57721188 is_allowed checks in mustache templates should use the instance
and not the page object.
Fix `is_allowed` Mustache helper

* don't infer context or resource type from `GGRC.page_instance()`
* require explicit context if `resource_type` is given as a string
Merge pull request #442 from reciprocity/feature/fix-is-allowed-checks

Feature/fix is allowed checks