Swap markdown images with own CDN

[BelieveInBunny]

closed by #67

[josecelano]

Now we have an image proxy with a cache in the backend.

Is that what you meant @BelieveInBunny?

[josecelano]

@da2ce7 did you add the "duplicate" label because of this issue?

[josecelano]

I think this is an concrete case of #67