Data provider simplification, tests, and documentation (#1997)

* Ignore env.test from source control

* Simplification of providers interface

* Synth tests

* Update money to use new find rates method

* Remove unused issues code

* Additional issue feature removals

* Update price data fetching and tests

* Update documentation for providers

* Security test fixes

* Fix self host test

* Update synth usage data access

* Remove AI pr schema changes

app/models/financial_assistant.rb

@@ -0,0 +1,11 @@
+class FinancialAssistant
+  include Provided
+
+  def initialize(chat)
+    @chat = chat
+  end
+
+  def query(prompt, model_key: "gpt-4o")
+    llm_provider = self.class.llm_provider_for(model_key)
+  end
+end