Show cash + holdings value for investment account view (#1046)

* Handle missing tickers in security price syncs

* Show combined cash and holdings value on account page

* Improve partial locals

app/controllers/account/cashes_controller.rb

@@ -0,0 +1,14 @@
+class Account::CashesController < ApplicationController
+  layout :with_sidebar
+
+  before_action :set_account
+
+  def index
+  end
+
+  private
+
+    def set_account
+      @account = Current.family.accounts.find(params[:account_id])
+    end
+end