POS Cart redesign (#5171)

* Move POS assets

* WIP

* Refactor into common Vue mixin

* Offcanvas updates

* Unifications across POS views

* POSData view fix

* Number and test fixes

* Update cart width

* Fix test

* More view unification

* Hide cart when emptied

* Validate cart

* Header improvement

* Increase remove icon size

* Animate add to cart action

* Offcanvas for mobile, sidebar for desktop

* ui+pos: updates icon size + badge + label

* Remove cart table headers

* Use same size for Cart and Shop headlines

* Update search placeholder

* Bump horizontal  input padding

* Increase sidebar width

* Bump badge font size

* Fix manipulating the quantity of line items

* Fix cart icon

* Update cart display

* updates empty button

* Rounded search input

* Remove cart button on desktop

* Fix dark accent color

* More accent fixes

* Fix plus/minus alignment

* Update BTCPayServer/Views/Shared/PointOfSale/Public/Cart.cshtml

* Apply suggestions from code review

---------

Co-authored-by: dstrukt <gfxdsign@gmail.com>

BTCPayServer/Plugins/PointOfSale/Models/ViewPointOfSaleViewModel.cs

@@ -93,7 +93,7 @@ namespace BTCPayServer.Plugins.PointOfSale.Models
                               .ToList();
             if (groups.Count == 0)
                 return;
-            groups.Insert(0, new KeyValuePair<string, string>("All items", "*"));
+            groups.Insert(0, new KeyValuePair<string, string>("All", "*"));
             AllCategories = new SelectList(groups, "Value", "Key", "*");
         }