Revert "It looks like this code was broken since it should be passing the context into the form_url parameter since that's what the superclass method does..."

This reverts commit 39a1c248b5bbc92f593d6457c2f68047499264bf.
Revert "Bring the `LinkInline` and `LinkedItemAdmin` back for some experimentation to try to discover why they originally deprecated `ForeignKeyAwareModelAdmin` and `InvisibleModelAdmin`"

This reverts commit a83179ea2c78ad9a0ec98512466b1a0d8510e551.

Reason is it is appears incapable of degenerating to the point of just being a link with some descriptive text, i.e. the screenshot in this diff demonstrates it is not what we're looking for:
https://github.com/specialunderwear/django-easymode/commit/f2f1a15fa0bb254750c4f0af8f8b615781c11445