Transforms Operations link into a dropdown

This commit updates the Operations link in the top navbar
into a dropdown to include a link to the environments
dashboard

Adds inline permission for Operations link

ee/app/views/dashboard/operations/_nav_link.html.haml

 - if can?(current_user, :read_operations_dashboard)
-  = nav_link(controller: 'operations') do
-    = link_to operations_path, title: _('Operations'), aria: { label: _('Operations') } do
+  %li.dropdown
+    %button.btn-link{ type: 'button', data: { toggle: 'dropdown' } }
       = sprite_icon('dashboard', size: 18)
+    .dropdown-menu
+      = link_to operations_path, class: 'dropdown-item', title: _('Environments'), aria: { label: _('Environments') } do
+        = _('Environments')
+      - if can?(current_user, :read_operations_dashboard)
+        = link_to operations_path, class: 'dropdown-item', title: _('Operations'), aria: { label: _('Operations') } do
+          = _('Operations')