Enforce size limit or timeout while parsing target configurations

[behnazh-w]

We are parsing various kinds of untrusted source files in JSON, YAML , and bash. The JSON standard library warns about parsing JSON files and suggests putting a limit on the size of input files.

This might not be a big issue because in the worst case Macaron might hang and consume unnecessary CPU and memory. When Macaron is integrated into CI/CD or any other automated service, we could consider adding some file size limits when parsing input files.