[Housekeeping] Refactor settings model (#165)

* [WIP] renamed current settings module and tables to have backup suffix

* Created new settings table, schema, and context

* Migrated from old settings module to new one

* Removed settings backup modules

* Added some tests and docs

lib/pinchflat_web/components/layouts/partials/upgrade_button_live.ex

@@ -30,7 +30,7 @@ defmodule Pinchflat.UpgradeButtonLive do
       |> String.downcase()
 
     if normalized_text == "got it!" do
-      Settings.set!(:pro_enabled, true)
+      Settings.set(pro_enabled: true)
 
       {:noreply, update(socket, :button_disabled, fn _ -> false end)}
     else