OSS-Detect-Backdoor rules should be embedded #372

OSS-Detect-Backdoor currently relies on the json rules being on disk due to the design of the oss-characteristic apis - which are in turn caused by use of specific app inspector APIs.

OSS-Detect-Backdoor should instead of copying the rules files to disk and reading them from there, embed the rules like in detect cryptography, to enable automatic rule verification in pipeline tests in particular.