fedora/openbsd/guix/rocky: URL fixes
- switch URLs of EOL versions of Fedora to archive locations
- switch old versions of OpenBSD to ftp.lysator.liu.se as location: it seems that ftp.eu.openbsd.org has not been around for a while now, and other *.openbsd.org HTTP mirrors do not have the old/EOL releases
- drop non-working guix URLs (see #89 (closed))
- rocky8.5: switch URLs to Rocky Linux Vault
Edited by Pino Toscano