fixed some missing extensions and typos

Please make sure your MR is ready to be merged !

• You added the changes in CHANGELOG.md
• You described the MR as below
• You updated the recalbox wiki
• You wrote a blog post on recalbox-blog

Changes :

• fixed some missing extensions inside es_system.cfg
• fixed some typos inside _readme.txt files
• removed fba_libretro from romfs-fba package
• added missing dreamcast bios infos
• added a default GlideN64's default config
• udpated default scrape

Closes #167 (closed)