software/seleniumserver: add JSON schemas

software/seleniumserver/instance-input-schema.json

+{
+  "$schema": "http://json-schema.org/draft-06/schema",
+  "type": "object",
+  "description": "Parameters to request selenium instance",
+  "additionalProperties": false,
+  "properties": {}
+}

software/seleniumserver/instance-output-schema.json

+{
+  "$schema": "http://json-schema.org/draft-06/schema",
+  "type": "object",
+  "description": "Values returned by Selenium instanciation",
+  "properties": {
+    "backend-url": {
+      "description": "Selenium hub URL",
+      "type": "string"
+    },
+    "url": {
+      "description": "Selenium instance URL",
+      "type": "string"
+    },
+    "admin-url": {
+      "description": "Selenium admin URL",
+      "type": "string"
+    },
+    "ssh-url": {
+      "description": "Selenium ssh URL",
+      "type": "string"
+    },
+    "ssh-fingerprint": {
+      "description": "Selenium ssh key fingerprint",
+      "type": "string"
+    },
+    "run-node-command": {
+      "description": "Command to run a local Selenium node",
+      "type": "string"
+    }
+  }
+}

software/seleniumserver/software.cfg.json

+{
+  "name": "Selenium Server",
+  "description": "Selenium server running chromium and firefox nodes",
+  "serialisation": "xml",
+  "software-type": {
+    "default": {
+      "title": "Default",
+      "software-type": "default",
+      "description": "Request a selenium server",
+      "request": "instance-input-schema.json",
+      "response": "instance-output-schema.json",
+      "index": 0
+    }
+  }
+}