✨ feat(footer): add link to remote repository

Adds two options, both defaulting to true if the remote repo URL is set:
* `show_remote_changes`: links the commit history of a post next to the updated date. (#109)
* `show_remote_source`: links to the site's repository on the footer.

templates/partials/footer.html

@@ -1,3 +1,4 @@
+{% set separator = config.extra.separator | default(value="•") %}
 <footer>
     <section>
         <nav class="socials nav-navs">
@@ -49,7 +50,35 @@
             {% endif %}
         </nav>
         <div class="credits">
-            <small>{%- if lang != config.default_language %} {{ trans(key="powered_by" | safe, lang=lang) }} {% else %} Powered by {% endif %} <a href="https://www.getzola.org" target="_blank">Zola</a> {%- if lang != config.default_language %} {{ trans(key="and" | safe, lang=lang) }} {% else %} & {% endif %} <a href="https://github.com/welpo/tabi" target="_blank">tabi</a></small>
+            {# Shows "Powered by Zola & tabi" #}
+            {# Shows link to remote repository if repository is set and `show_remote_source` is not false #}
+            {% set show_source = config.extra.show_remote_source | default(value=true) %}
+            <small>
+                {%- if lang != config.default_language -%} 
+                    {{ trans(key="powered_by" | safe, lang=lang) }} 
+                {%- else -%} 
+                    Powered by
+                {%- endif -%} 
+                &nbsp;<a href="https://www.getzola.org" target="_blank">Zola</a>&nbsp;
+        
+                {%- if lang != config.default_language -%}
+                    {{ trans(key="and" | safe, lang=lang) }} 
+                {%- else -%} 
+                    &
+                {%- endif -%} 
+                &nbsp;<a href="https://github.com/welpo/tabi" target="_blank">tabi</a>
+
+                {%- if config.extra.remote_repository_url and show_source -%}
+                &nbsp;{{ separator }}
+                    <a href="{{ config.extra.remote_repository_url }}" target="_blank">
+                        {%- if lang != config.default_language -%}
+                            {{ trans(key="site_source" | safe, lang=lang) }}
+                        {%- else -%}
+                            Site source
+                        {%- endif -%}
+                    </a>
+                {%- endif -%}
+            </small>
         </div>
     </section>