Update processor to allow Unfetter to startup on non-internet access machines

[infosec-alchemist]

Customers might want to try and run Unfetter in a lab environment without continous access to Unfetter. Make at least the following changes

• [ ] Add the MITRE attack enterprise.json to the file repo for processor to pick up. Provide this as an option for the location of the GitHub repository, so Processor can try for internet access first.
• [ ] Assuming that internet access is not available, the processor seems to have problems if it can't connect to the internet OR the mongo database. Which breaks the unfetter-discover-api. Processor should be considered optional, and may not even run by the customer.
• [ ] Ensure that rerunning processor and getting updated MITRE Enterprise data will update old/legacy enterprise.json