Self-host Lumeex and Instameex images instead of hotlinking them from git.djeex.fr

Same failure as the icon collections: img-src 'self' in the CSP silently
blocked these, they just happened to load once from browser cache before
this fix made them visibly broken.

content/en/5.nonsense/2.python/3.lumeex.md

@@ -6,13 +6,13 @@ description: Lumeex is a static photo gallery site generator built with Python,
 
 :ellipsis{left=0px width=40rem top=10rem blur=140px zIndex=60}
 <div align="center">
-  <img src="https://git.djeex.fr/Djeex/lumeex/raw/branch/main/illustration/logo.svg" alt="Lumeex Screenshot" width="300"/>
+  <img src="/img/nonsense/lumeex-logo.svg" alt="Lumeex logo" width="300"/>
 </div>
 <div align="center">
 <p>Yet another minimalist, lightweight photo gallery static site generator.</p>
 </div>
 <div align="center">
-  <img src="https://git.djeex.fr/Djeex/lumeex/raw/branch/main/illustration/lumeex.png" alt="Lumeex Screenshot" />
+  <img src="/img/nonsense/lumeex.png" alt="Lumeex gallery homepage" />
 </div>
 
 ---
@@ -28,7 +28,7 @@ Eventually, after getting good results, I figured I might as well go all the way
 That’s how **Lum[eex]{style="color: #1ad6ff"}** was born.
 
 <div align="center">
-  <img src="https://git.djeex.fr/Djeex/lumeex/raw/branch/main/illustration/lumeex-webui.png" alt="Lumeex Screenshot" />
+  <img src="/img/nonsense/lumeex-webui.png" alt="Lumeex configuration web UI" />
 </div>
 
 ---