Add bilingual French/English support with Hugo multilingual config

Configure Hugo multilingual mode (fr default, en secondary) with
Hextra's language-switch menu entry, and translate all existing
content pages to English using Hugo's per-file language suffix
convention (.en.md alongside .fr.md).

content/netlab/_index.en.md

@@ -0,0 +1,16 @@
+---
+title: "Netlab"
+cascade:
+  type: docs
+---
+
+<!-- markdownlint-disable MD033 MD034-->
+
+{{< hextra/hero-subtitle >}}
+  A deep dive into NetLabs
+{{< /hextra/hero-subtitle >}}
+
+{{< cards >}}
+  {{< card link="/en/netlab/netlab/" title="What is a Netlab?" subtitle="Why and how we use NetLab" icon="science" >}}
+  {{< card link="/en/netlab/first_lab/" title="My First NetLab" subtitle="How to deploy a NetLab using DevPod" icon="docker" >}}
+{{< /cards >}}