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/controllers/import/mappings_controller_test.rb

@@ -0,0 +1,29 @@
+require "test_helper"
+
+class Import::MappingsControllerTest < ActionDispatch::IntegrationTest
+  setup do
+    sign_in @user = users(:family_admin)
+
+    @import = imports(:transaction)
+  end
+
+  test "updates mapping" do
+    mapping = import_mappings(:one)
+    new_category = categories(:income)
+
+    patch import_mapping_path(@import, mapping), params: {
+      import_mapping: {
+        mappable_type: "Category",
+        mappable_id: new_category.id,
+        key: "Food"
+      }
+    }
+
+    mapping.reload
+
+    assert_equal new_category, mapping.mappable
+    assert_equal "Food", mapping.key
+
+    assert_redirected_to import_confirm_path(@import)
+  end
+end