Issue #3426475 by Grimreaper: Dropdown: implements menu alignment

Closes #3426475

templates/patterns/dropdown/dropdown.ui_patterns.yml

@@ -149,6 +149,34 @@ dropdown:
       preview: false
       allow_expose: true
       allow_token: true
+    dropdown_menu_start:
+      type: "select"
+      label: "Menu alignment: start"
+      description: "To align left/start the dropdown menu with the given breakpoint or larger."
+      options:
+        start: "all"
+        sm-start: "from small"
+        md-start: "from medium"
+        lg-start: "from large"
+        xl-start: "from extra large"
+        xxl-start: "from extra extra large"
+      preview: ''
+      allow_expose: true
+      allow_token: true
+    dropdown_menu_end:
+      type: "select"
+      label: "Menu alignment: end"
+      description: "To align right/end the dropdown menu with the given breakpoint or larger."
+      options:
+        end: "all"
+        sm-end: "from small"
+        md-end: "from medium"
+        lg-end: "from large"
+        xl-end: "from extra large"
+        xxl-end: "from extra extra large"
+      preview: ''
+      allow_expose: true
+      allow_token: true
     heading_level:
       type: "select"
       label: "Heading level for header items"