Strongly-typed ResourceID

**Is your feature request related to a problem? Please describe.**
Given a full resource ID to a child resource have the ability to create a resource ID of the parent.

Excerpted from #3173: some RPs provide a full resource ID to some other (child) resources. For example: Microsoft.Network/loadBalancers provides the full ip configuration resource ID in its properties 'backendAddressPools[0].properties.backendIPConfigurations[0].id' as:

```json
{
"id": "/subscriptions/<sub>/resourceGroups//providers/Microsoft.Compute/virtualMachineScaleSets//virtualMachines/0/networkInterfaces//ipConfigurations/"
},
```</sub>

**Describe the solution you'd like**
* Idea 1: have a type `resourceID` that can be initiated using a string (or the output of `*resourceId()` function). The type could allow `.parent` to obtain the parent resource ID.

* Idea 2: similar to above but using a new `parentResourceId()` function

The issue names no implementation files or tests; start with issue #3173 and the full child resource ID example here. Compare the proposed strongly typed resourceID and parentResourceId approaches, then define and validate the selected behavior for deriving a parent resource ID from a full child ID.

Written by the indexing model from the issue text.