Investment Portfolio Sync (#974)

* Add investment portfolio models

* Add portfolio to demo data

* Setup initial tests

* Rough sketch of sync logic

* Clean up trade sync logic

* Add trade validation

* Integrate trades into sync process

db/migrate/20240710182728_create_security_prices.rb

@@ -0,0 +1,12 @@
+class CreateSecurityPrices < ActiveRecord::Migration[7.2]
+  def change
+    create_table :security_prices, id: :uuid do |t|
+      t.string :isin
+      t.date :date
+      t.decimal :price, precision: 19, scale: 4
+      t.string :currency, default: "USD"
+
+      t.timestamps
+    end
+  end
+end