Account namespace updates: part 1 (#893)

* Rename accountable types

* Merge conflicts

* Fix broken tests

* Add back sidebar changes

app/models/investment.rb

@@ -0,0 +1,16 @@
+class Investment < ApplicationRecord
+  include Accountable
+
+  SUBTYPES = [
+    [ "Brokerage", "brokerage" ],
+    [ "Pension", "pension" ],
+    [ "Retirement", "retirement" ],
+    [ "401(k)", "401k" ],
+    [ "529 plan", "529_plan" ],
+    [ "Health Savings Account", "hsa" ],
+    [ "Mutual Fund", "mutual_fund" ],
+    [ "Roth IRA", "roth_ira" ],
+    [ "Roth 401k", "roth_401k" ],
+    [ "Angel", "angel" ]
+  ].freeze
+end