feat: add nethergamesmc core install flow

manifests/cores.json

@@ -0,0 +1,66 @@
+{
+  "pmmp": {
+    "name": "PocketMine-MP",
+    "edition": "bedrock",
+    "runtime": "php",
+    "default_port": 19132,
+    "protocol": "udp",
+    "default_dir": "/opt/minecraft/pmmp",
+    "supports_protocols": ["udp"],
+    "supported_services": ["systemd", "tmux-systemd", "none"]
+  },
+  "paper": {
+    "name": "Paper",
+    "edition": "java",
+    "runtime": "java",
+    "java_version": 21,
+    "default_port": 25565,
+    "protocol": "tcp",
+    "default_dir": "/opt/minecraft/paper",
+    "supports_protocols": ["tcp"],
+    "supported_services": ["systemd", "tmux-systemd", "none"]
+  },
+  "purpur": {
+    "name": "Purpur",
+    "edition": "java",
+    "runtime": "java",
+    "java_version": 21,
+    "default_port": 25565,
+    "protocol": "tcp",
+    "default_dir": "/opt/minecraft/purpur",
+    "supports_protocols": ["tcp"],
+    "supported_services": ["systemd", "tmux-systemd", "none"]
+  },
+  "velocity": {
+    "name": "Velocity",
+    "edition": "proxy",
+    "runtime": "java",
+    "java_version": 21,
+    "default_port": 25577,
+    "protocol": "tcp",
+    "default_dir": "/opt/minecraft/velocity",
+    "supports_protocols": ["tcp"],
+    "supported_services": ["systemd", "tmux-systemd", "none"]
+  },
+  "powernukkitx": {
+    "name": "PowerNukkitX",
+    "edition": "bedrock",
+    "runtime": "java",
+    "java_version": 21,
+    "default_port": 19132,
+    "protocol": "udp",
+    "default_dir": "/opt/minecraft/powernukkitx",
+    "supports_protocols": ["udp"],
+    "supported_services": ["systemd", "tmux-systemd", "none"]
+  },
+  "nethergamesmc": {
+    "name": "NetherGamesMC",
+    "edition": "bedrock",
+    "runtime": "php",
+    "default_port": 19132,
+    "protocol": "udp",
+    "default_dir": "/opt/minecraft/nethergamesmc",
+    "supports_protocols": ["udp"],
+    "supported_services": ["systemd", "tmux-systemd", "screen", "none"]
+  }
+}