CSV Imports Overhaul (Transactions, Trades, Accounts, and Mint import support) (#1209)

* Remove stale 1.0 import logic and model

* Fresh start

* Checkpoint before removing nav

* First working prototype

* Add trade, account, and mint import flows

* Basic working version with tests

* System tests for each import type

* Clean up mappings flow

* Clean up PR, refactor stale code, tests

* Add back row validations

* Row validations

* Fix import job test

* Fix import navigation

* Fix mint import configuration form

* Currency preset for new accounts

test/models/import/mapping_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class Import::MappingTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end