Standardize all icon-based actions to buttons

Use a combination of ghost and soft, with button groups where
appropriate. Also remove unnecessary negative margins, and pad around
for ease of use on mobile.

lib/music_library_web/live/artist_live/show.html.heex

@@ -22,13 +22,15 @@
           </button>
           <.dropdown id={"actions-#{@artist.musicbrainz_id}"} placement="bottom-end">
             <:toggle>
-              <span class="sr-only">{gettext("Actions")}</span>
-              <.icon
-                name="hero-ellipsis-vertical"
-                class="-mt-1 h-5 w-5 text-zinc-500 dark:text-zinc-400 cursor-pointer"
-                aria-hidden="true"
-                data-slot="icon"
-              />
+              <.button variant="ghost">
+                <span class="sr-only">{gettext("Actions")}</span>
+                <.icon
+                  name="hero-ellipsis-vertical"
+                  class="h-5 w-5 text-zinc-500 dark:text-zinc-400 cursor-pointer"
+                  aria-hidden="true"
+                  data-slot="icon"
+                />
+              </.button>
             </:toggle>
             <.focus_wrap id={"actions-#{@artist.musicbrainz_id}-focus-wrap"}>
               <.dropdown_link