Improvement: Style Stripe information box.
Improvement: Update codebase to have sync RCP with RC Free.
Feature: Allow shortcode [restrict] to use levels as number in attribute `userlevel`.
Improvement: Add a new feature in the RCP settings to let the user add Stripe Descriptor and Suffix.
Improvement: Add a new feature to allow switching free memberships if the user has already used or trialed a free membership.
Fix: PHP 8.x. Fix string format while displaying the percentage symbol on the "Discount Codes" page.
