feat: added page for community packages, not linked from menu yet

Author: ntamas

_layouts/page.html

@@ -0,0 +1,21 @@
+---
+layout: default
+---
+
+<div class="container">
+  <div class="row">
+    <div class="col-md-12">
+      <div class="bs-docs-section">
+        <div class="post-header">
+          <h1>{{ page.title }}</h1>
+          {% if page.title %}
+          <div class="post-authors text-muted">{{ page.authors | default: site.authors | array_to_sentence_string }}</div>
+	        {% endif %}
+          <div class="post-time"><time class="text-muted">{{ page.date | date_to_string: "ordinal", "US" }}</time></div>
+        </div>
+
+        {{ content | redir_docs }}
+      </div>
+    </div>
+  </div>
+</div>

community/packages.md

@@ -0,0 +1,15 @@
+---
+layout: page
+mainheader: Community Packages
+lead: Third-party interfaces and packages maintained by the community
+---
+
+## Third-party interfaces
+
+* [matlab-igraph](https://davidrconnell.github.io/matlab-igraph/) - a Matlab interface for igraph
+
+* [Igraphs.jl](https://github.com/JuliaGraphs/IGraphs.jl) - Julia wrapper around igraph
+
+## Related projects
+
+