[5.x] Improve recursive behavior when using route data in computed values

[JohnathonKoster]

This PR fixes the issue described in #11853. When a computed value triggers the routeData method and the collection has a structure, you can end up in an infinite loop when fetching the entry.

This PR wraps computed values in a Value object to defer their execution only when resolving routeData. This is accomplished with two new methods:

• getComputedData
• getValues

Both of these methods allow the caller to wrap computed callbacks in a Value object. These methods are now used in the existing computedData and values methods. This was done to keep the signatures of these methods the same.

It will still be possible to cause infinite loops, depending on what the user is doing. The changes in #11854 will help with those scenarios.