wishlist: remove some deprecated softwares

[OniriCorpe]

deprecated:

• restya: seems dead, see Project dead? RestyaPlatform/board#4426
• script-server, website is gone, no commit for 4 years, seems dead: https://github.com/bugy/script-server
• cagette: repo is gone, now a proprietary software, see: https://wiki.cagette.net/devfaq
• wikiless: website and repo are gone

not self-hostable:

• megaglest: it's a graphical computer game