document user endpoints (#11894)

* document user endpoints, allow for empty request/response bodies

* document more user endpoints, improve debugging output if no details are specified

* document some more user endpoints

* minor cleanup

* FIX: flakey tests due to bad regex

spec/requests/api/schemas/json/user_delete_request.json

@@ -0,0 +1,17 @@
+{
+  "additionalProperties": false,
+  "properties": {
+    "delete_posts": {
+      "type": "boolean"
+    },
+    "block_email": {
+      "type": "boolean"
+    },
+    "block_urls": {
+      "type": "boolean"
+    },
+    "block_ip": {
+      "type": "boolean"
+    }
+  }
+}