no issue
- the `memberRecord` getter on the members activity controller was
returning the direct result of `store.findRecord()` which in reality is
a `PromiseObject` that is a type of proxy. Although templates handle
this OK, any JS code using the object needs to know that it's not a
typical type of object and has to use `.get()` for all property access
to avoid errors
- switched `memberRecord` from a getter to a resource so we have more
control over the returned object and loading lifecycle
- added a `MemberFetcher` resource class that awaits the result of the
store find and only then sets the value meaning we always have a fully
resolved model object
- being a resource the fetch will only occur when the `member` id
property changes, unlike the getter which performed the fetch every time
it was accessed
