Apply UI authorization to Member LiveViews (Index and Show)

Gate New Member button, Edit and Delete links with can?/3.
Edit button on Member Show visible only when user can update the member.

lib/mv_web/live/member_live/show.ex

@@ -39,9 +39,11 @@ defmodule MvWeb.MemberLive.Show do
           {MvWeb.Helpers.MemberHelpers.display_name(@member)}
         </h1>
 
-        <.button variant="primary" navigate={~p"/members/#{@member}/edit?return_to=show"}>
-          {gettext("Edit Member")}
-        </.button>
+        <%= if can?(@current_user, :update, @member) do %>
+          <.button variant="primary" navigate={~p"/members/#{@member}/edit?return_to=show"}>
+            {gettext("Edit Member")}
+          </.button>
+        <% end %>
       </div>
 
       <%!-- Tab Navigation --%>