Add ContractSpec.jsonSchema() method to generate schemas (#889)

* Also add tests that generate input data based on JSON schema
* Fixup: make json-schema-faker a devDep

.gitignore

@@ -9,3 +9,6 @@
 .DS_Store
 .idea/
 js-stellar-base/
+
+test/unit/out/
+.vscode/launch.json

package.json

@@ -89,6 +89,7 @@
     "@types/chai": "^4.3.6",
     "@types/detect-node": "^2.0.0",
     "@types/eventsource": "^1.1.12",
+    "@types/json-schema": "^7.0.15",
     "@types/lodash": "^4.14.199",
     "@types/mocha": "^10.0.2",
     "@types/node": "^20.8.10",
@@ -139,14 +140,15 @@
     "typescript": "^5.3.3",
     "utility-types": "^3.7.0",
     "webpack": "^5.88.2",
+    "json-schema-faker": "^0.5.4",
     "webpack-cli": "^5.0.1"
   },
   "dependencies": {
+    "@stellar/stellar-base": "10.0.0",
     "axios": "^1.6.0",
     "bignumber.js": "^9.1.2",
     "eventsource": "^2.0.2",
     "randombytes": "^2.1.0",
-    "@stellar/stellar-base": "10.0.0",
     "toml": "^3.0.0",
     "urijs": "^1.19.1"
   }