YITH WooCommerce Deposits and Down Payments Premium 2.19.0

* New: support for WooCommerce 4.2
* Update: plugin framework
* Tweak: improved grand total calculation, when propagating coupons
* Fix: issue with balance totals calculation, when both deposit and balance have shippings
* Dev: new filters to show deposit in product_page shortcode

* New: support for WooCommerce 4.1
* Update: plugin framework
* Tweak: added specific classes to order action buttons
* Tweak: wrapped product note inside div
* Tweak: added classes and attributes to make my deposits table responsive
* Fix: issue with calculate shipping form on variable products
* Fix: added check on "deposit expiring" email, to avoid possible fatal error when suborder no longer exists
* Fix: issue wit fee handling when printing out balance subtotal
* Fix: bundle price issue when deposit is not enabled on product in combination with YITH WooCommerce Product Bundle
* Dev: added trigger yith_wcdp_updated_deposit_form

* New: support for WordPress 5.4
* New: support for WooCommerce 4.0
* New: added shortcode yith_wcdp_desposit_value
* Tweak: improved order filtering
* Tweak: adds balance lines to order review
* Fix: PHP Fatal error: Uncaught Error: Call to a member function is_purchasable() on bool
* Dev: added yith_wcdp_before_suborders_create and yith_wcdp_after_suborders_create actions