feat: list rocknix cores per device

ROCKNIX builds a different emulator set per SoC, and without a target
list an H700 handheld received the PS2, PS3 and GameCube firmware of
emulators its image lacks. The new target scraper reads the emulators
metapackage per device; seven cores ROCKNIX ships get profiles and the
Super Famicom Box ROMs one of them needs are collected.

platforms/_registry.yml

@@ -374,6 +374,8 @@ platforms:
     logo: https://avatars.githubusercontent.com/u/152618023
     scraper: rocknix
     schedule: weekly
+    target_scraper: rocknix_targets
+    target_source: https://github.com/ROCKNIX/distribution/blob/next/projects/ROCKNIX/packages/virtual/emulators/package.mk
     install:
       detect:
       - os: linux

platforms/targets/_overrides.yml

@@ -112,3 +112,19 @@ retropie:
     _default:
       # Homebrew game scriptmodule, not an emulator.
       remove_cores: [superflappybirds]
+
+rocknix:
+  targets:
+    _default:
+      # Runtimes and launchers the emulators metapackage installs beside the
+      # emulators: x86 translation (box64, box86), Windows (wine), the Steam
+      # and Heroic clients, and PortMaster, which installs ports.
+      remove_cores:
+        - box64
+        - box86
+        - heroic
+        - portmaster
+        - steam
+        - wine
+    amd64:
+      aliases: [x86_64, pc]