Afform - delete unused, nonfunctional apis

[colemanw]

Overview

Removes a couple unused APIs from the Afform extension. They don't do anything.

Before

Code present, does nothing.

After

Code gone. Still does nothing but with fewer lines of code :)

Comments

I can't remember what these were supposed to be for. Maybe @totten does.

[civibot]

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[totten]

I can't remember what these were supposed to be for.

"Palette" ==> List of things that you can select and add to a canvas. These are basically small snippets of HTML that one drops into the canvas.

The earlier intent had been to model the palette in a way that gave API visibility (i.e. the data-model of the palette would be clearly defined/tracked/searchable in the conventional way). But, as it stands, I think this is organized privately via CRM_AfformAdmin_Utils::getGuiSettings() and client-side code.

At this point, to get the benefit of a conventionally-shaped API for palette content, one would have to approach it is a refactoring subproject that's more attuned to the de facto model. Not much point keeping the skeleton around.

r-tests are passing. Merging.