Validate token audience before running gather

[rgmz]

This checks that the provided token is for graph.windows.net before running roadrecon gather, as mentioned in #111.

Add a sanity check in run that the token is for graph.windows.net

As with #113, this could be prettier but I tried to keep the changes minimal:

$ roadrecon gather
Traceback (most recent call last):
  File "/home/user/code/ROADtools/.venv/bin/roadrecon", line 8, in <module>
    sys.exit(main())
             ~~~~^^
  File "/home/user/code/ROADtools/roadrecon/roadtools/roadrecon/main.py", line 125, in main
    gathermain(args)
    ~~~~~~~~~~^^^^^^
  File "/home/user/code/ROADtools/roadrecon/roadtools/roadrecon/gather.py", line 740, in main
    raise ValueError("token audience must be 'https://graph.windows.net', not '%s'" % aud)
ValueError: token audience must be 'https://graph.windows.net', not 'https://graph.microsft.com'

[dirkjanm]

hey, appreciate the PR, however there's already some token validation in roadtx that we can re-use that uses the functionality from roadlib. we also need to take into account multiple valid audiences, as added in 5f87886

[rgmz]

No worries, that's definitely a much better implementation!