Add term page layout

This commit introduces a layout for term pages, displaying
posts associated with a taxonomy term.

- Adds `layouts/_default/term.html` to display term pages.
- Uses `taxonomy_posts.html` partial for listing posts.
- Includes header and footer partials.

Author: mr-karan

layouts/_default/term.html

@@ -0,0 +1,6 @@
+{{ partial "header.html" . }}
+	<div class="container wrap">
+		{{ partial "taxonomy_posts.html" . }}
+	</div>
+
+ {{ partial "footer.html" . }}