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

app/controllers/transactions/bulk_deletions_controller.rb

@@ -0,0 +1,12 @@
+class Transactions::BulkDeletionsController < ApplicationController
+  def create
+    destroyed = Current.family.entries.destroy_by(id: bulk_delete_params[:entry_ids])
+    destroyed.map(&:account).uniq.each(&:sync_later)
+    redirect_back_or_to transactions_url, notice: "#{destroyed.count} transaction#{destroyed.count == 1 ? "" : "s"} deleted"
+  end
+
+  private
+    def bulk_delete_params
+      params.require(:bulk_delete).permit(entry_ids: [])
+    end
+end