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

app/models/trade_import.rb

@@ -0,0 +1,52 @@
+class TradeImport < Import
+  def import!
+    transaction do
+      mappings.each(&:create_mappable!)
+
+      rows.each do |row|
+        account = mappings.accounts.mappable_for(row.account)
+        security = Security.find_or_create_by(ticker: row.ticker)
+
+        entry = account.entries.build \
+          date: row.date_iso,
+          amount: row.signed_amount,
+          name: row.name,
+          currency: row.currency,
+          entryable: Account::Trade.new(security: security, qty: row.qty, currency: row.currency, price: row.price),
+          import: self
+
+        entry.save!
+      end
+    end
+  end
+
+  def mapping_steps
+    [ Import::AccountMapping ]
+  end
+
+  def required_column_keys
+    %i[date ticker qty price]
+  end
+
+  def column_keys
+    %i[date ticker qty price currency account name]
+  end
+
+  def dry_run
+    {
+      transactions: rows.count,
+      accounts: Import::AccountMapping.for_import(self).creational.count
+    }
+  end
+
+  def csv_template
+    template = <<-CSV
+      date*,ticker*,qty*,price*,currency,account,name
+      05/15/2024,AAPL,10,150.00,USD,Trading Account,Apple Inc. Purchase
+      05/16/2024,GOOGL,-5,2500.00,USD,Investment Account,Alphabet Inc. Sale
+      05/17/2024,TSLA,2,700.50,USD,Retirement Account,Tesla Inc. Purchase
+    CSV
+
+    CSV.parse(template, headers: true)
+  end
+end