`json-rules-engine-simplified` is a necessary dependency

[ivarprudnikov]

Issue:
Using react-jsonschema-form-conditionals alone with json-rules-engine fails to resolve dependency of json-rules-engine-simplified.

Expected behavior:
react-jsonschema-form-conditionals and usage of json-rules-engine should not produce dependency issue.

Cause:
utils.js depends on json-rules-engine-simplified/lib/utils

Suggestion:
Move json-rules-engine-simplified dependency out of devDependencies into dependencies block in package.json.