Account:: namespace simplifications and cleanup (#2110)

* Flatten Holding model

* Flatten balance model

* Entries domain renames

* Fix valuations reference

* Fix trades stream

* Fix brakeman warnings

* Fix tests

* Replace existing entryable type references in DB

test/support/entries_test_helper.rb

@@ -0,0 +1,47 @@
+module EntriesTestHelper
+  def create_transaction(attributes = {})
+    entry_attributes = attributes.except(:category, :tags, :merchant)
+    transaction_attributes = attributes.slice(:category, :tags, :merchant)
+
+    entry_defaults = {
+      account: accounts(:depository),
+      name: "Transaction",
+      date: Date.current,
+      currency: "USD",
+      amount: 100,
+      entryable: Transaction.new(transaction_attributes)
+    }
+
+    Entry.create! entry_defaults.merge(entry_attributes)
+  end
+
+  def create_valuation(attributes = {})
+    entry_defaults = {
+      account: accounts(:depository),
+      name: "Valuation",
+      date: 1.day.ago.to_date,
+      currency: "USD",
+      amount: 5000,
+      entryable: Valuation.new
+    }
+
+    Entry.create! entry_defaults.merge(attributes)
+  end
+
+  def create_trade(security, account:, qty:, date:, price: nil)
+    trade_price = price || Security::Price.find_by!(security: security, date: date).price
+
+    trade = Trade.new \
+      qty: qty,
+      security: security,
+      price:    trade_price,
+      currency: "USD"
+
+    account.entries.create! \
+      name: "Trade",
+      date: date,
+      amount: qty * trade_price,
+      currency: "USD",
+      entryable: trade
+  end
+end