Prepare something special for archlinux-2021.04.01-x86_64.iso

I think we should prepare something amusing for April's official ISO (archlinux-2021.04.01-x86_64.iso). It doesn't necessarily need to be grand, just as long as it caches the eye. 😄

For now, I have this in mind:

Any ideas of what else to add?

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The plan:

1. merge the changes,
2. tag archiso v52,
3. revert the changes at the end of April.