feat: pack every core batocera offers in es

Batocera's cores were read from configgen-defaults.yml, one per system,
and a hand-kept registry list overrode even that; DOSBox Staging,
melonDS DS and nine other cores a user can pick in ES were outside the
pack, while mamemess, which Batocera does not ship, was in. The
scraper now reads es_systems.yml, the registry list is gone, and the
target scraper names standalone emulators (amiberry, fsuae, vice)
instead of only the machines listed under them.

scripts/scraper/targets/batocera_targets_scraper.py

@@ -228,7 +228,7 @@ def _parse_es_systems(text: str) -> dict[str, list[str]]:
         emulators = system_data.get("emulators")
         if not isinstance(emulators, dict):
             continue
-        for _group_name, group_data in emulators.items():
+        for group_name, group_data in emulators.items():
             if not isinstance(group_data, dict):
                 continue
             for core_name, core_data in group_data.items():
@@ -237,9 +237,13 @@ def _parse_es_systems(text: str) -> dict[str, list[str]]:
                 require = core_data.get("requireAnyOf", [])
                 if not isinstance(require, list):
                     continue
+                # A standalone emulator is its own core: amiberry, fsuae and
+                # vice list machines under their name, and the package that
+                # builds a machine builds the emulator.
+                names = [core_name] if group_name == "libretro" else [group_name, core_name]
                 for pkg_flag in require:
                     if isinstance(pkg_flag, str):
-                        package_to_emulators.setdefault(pkg_flag, []).append(core_name)
+                        package_to_emulators.setdefault(pkg_flag, []).extend(names)
 
     return package_to_emulators