Seek interfaces, skip dummy, fix region codes

[eb3095]

Proposed Commit Message

Seek interfaces on Vultr opposed to using the first, fix region codes

We were seeing issues where if anything showed up before the expected first adapter, booting could fail. This switches to seeking for a working interface to handle edge cases.

Also fixes region code handling.

Checklist:

• [ X ] My code follows the process laid out in the documentation
• [ X ] I have updated or added any unit tests accordingly
• [ X ] I have updated or added any documentation accordingly

[TheRealFalcon]

Looks good, but please run tox -e format so the code passes the black check.