Consolidate list template

Rearrange styles and templates to use the list partial templates in termlite.

assets/css/050_photos.css

@@ -79,8 +79,9 @@
   }
 }
 
-.photostream-grid {
-  grid-column: full-start / full-end;
+
+.main--photostream .main__posts-by-year {
+  grid-column: main-start / main-end;
   display: grid;
   grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
 
@@ -88,24 +89,8 @@
     margin-block-end: var(--space-l);
   }
 
-  > .photostream-grid__date-heading {
-    align-items: center;
-    background-color: var(--gray6);
-    display: flex;
-    height: 100%;
-    justify-content: center;
-    line-height: 1;
-    width: 100%;
-
-    > h2 {
-      font-size: var(--text-xxl);
-      margin: 0;
-
-      &::after {
-        color: var(--text-color-secondary);
-        content: ">";
-      }
-    }
+  .main__section-heading {
+    grid-column: 1 / -1;
   }
 }