fix: games tools write whole files, name options

The games importers wrote through fixed .part names, the new options had
no help text, and romfolders stopped on the first setup the offline cache
lacked. RetroArch's rom folder map is regenerated from its source spec
(path null, as the schema says). The installer's Python 3.8 job imports
the games tests without pyyaml, so the region rules load lazily.

platforms/romfolders/retroarch.yml

@@ -7,13 +7,13 @@ sources:
     commit: 69a4f0ea1e8aaf442ae4858f2e7f2b31a1776576
     tag: v1.22.2
 roms_root:
-  path: none
+  path: null
   from_bios: null
   source_ref: "os configuration.c:3126,3295-3298"
 case_sensitive: null
 notes:
 - "RetroArch alone defines no rom folder. rgui_browser_directory starts empty and only a platform default\
-  \ fills it, which no desktop driver sets (os configuration.c:3126,3295-3298). The path none says so."
+  \ fills it, which no desktop driver sets (os configuration.c:3126,3295-3298)."
 - "Content reaches a core through playlists built by scanning against the content databases (os tasks/task_database.c),\
   \ or from the file browser with a core the user picks. The system can only come from the game itself\
   \ or from a folder the user names."