Account Sync should happen at login, 1x per day, OR on-demand (#594)

* Add last_sync_date to accounts table

* Always sync Account after Valuation or Transaction creation, update, or deletion.

Skip sync if user clicks "sync" button without changing anything

* Sync user accounts daily based on last_login_at

db/migrate/20240401213443_add_last_sync_date_to_accounts.rb

@@ -0,0 +1,5 @@
+class AddLastSyncDateToAccounts < ActiveRecord::Migration[7.2]
+  def change
+    add_column :accounts, :last_sync_date, :date
+  end
+end

db/migrate/20240403192649_add_last_login_at_to_users.rb

@@ -0,0 +1,5 @@
+class AddLastLoginAtToUsers < ActiveRecord::Migration[7.2]
+  def change
+    add_column :users, :last_login_at, :datetime
+  end
+end