Recursive scan, lazy content loading, include forks, b64 decode, catch ResolutionErrors & tweak logging 😮‍💨

[TheTeaCat]

Blocked by #3

• Implements scanning the repo contents recursively, as I didn't realise .get_content() isn't recursive. An alternative is to use git trees, but this was easier and works for now.
• Makes loading the file contents lazy so the file extension is checked first before bothering to load it, as scanning repos with large irrelevant files was slow.
• Removes skipping forked repos
• Adds ResolutionErrors to the try catch around the prance resolution
• Adds a missing b64 decode to file contents
• Tweaks logging to be a bit nicer to read & output the response from the Firetail SaaS upon API creation