sdk: readable clients (no Empty wrapper, no unused error module), documented examples with tests

examples/consumer/imports/secrets.json

@@ -1,10 +1,6 @@
 {
   "components": {
     "schemas": {
-      "Empty": {
-        "description": "Empty parameters for methods without arguments.",
-        "type": "object"
-      },
       "GetParams": {
         "description": "The name of a secret to read.",
         "properties": {
@@ -54,10 +50,7 @@
           "type": "null"
         }
       },
-      "summary": "Open the in-memory vault and publish its endpoint.",
-      "x-sausage-params": {
-        "$ref": "#/components/schemas/Empty"
-      }
+      "summary": "Open the in-memory vault and publish its endpoint."
     }
   ],
   "openrpc": "1.2.6",