Allow field def containedExamples to render

[tintinthong]

This PR builds on on #2189 and #2105.

Previously, Specs could not render fields

Now, Specs render fields based upon the code ref it contains

Further Note

Here, Specs are 1 to 1 with code refs so it doesn't really need a "different" subclass rendering of the field when showing containedExamples. However, if we want to include the UI affordance for selecting a template for field that is of a particular type, we can easily do so by dynamically specifying the typeConstraint (but this might not be the concern of Spec).

I saw some rendering thing with the ColorField. I'll look into it independently

[github-actions]

Host Test Results

    1 files  ±0      1 suites  ±0   25m 16s ⏱️ +14s
801 tests +3  799 ✔️ +3  2 💤 ±0  0 ❌ ±0 
806 runs  +3  804 ✔️ +3  2 💤 ±0  0 ❌ ±0 

Results for commit 11b19f1. ± Comparison against base commit 160dab0.

♻️ This comment has been updated with latest results.

[tintinthong]

Currently, some issues with some fields. Color is another one

[tintinthong]

Pause review here. There is some bug on primitive handling which requires more card-api tweaks

[tintinthong]

Pause review here. There is some bug on primitive handling which requires more card-api tweaks

The bug in here is when serializing (im not sure in deserializing) URL extends StringField.

URL is a primitive so it doesn't serialize meta.fields. That means it doesn't have the ability to render a different template.

[tintinthong]

I have updated #2189. And will continue work once that is merged

[tintinthong]

After some consideration,

I think handling of primitive for polymorphism should be out-of-scope of this PR.

It is quite involve to get this to work and might invite some workaround patterns. So it would be good to check-in with Ed in how to appraoch this