Support importing characters from PoE API

[Wires77]

Initially copied from: PathOfBuildingCommunity/PathOfBuilding#8525

This is a very early implementation of PoB interacting with PoE's OAuth API. I wanted to get this out there in draft for early reviews and to organize my thoughts while I check things off the list:

Required for MVP:

• TODO statements
• Hardening/Logging
• Investigate if SO_EXCLUSIVEADDRUSE is set in luasocket (part of hardening)
  -- Pretty sure this only applies to pre-Windows 2003 installs and people running PoB in compatibility mode for that. I did submit a PR to luasocket before realizing that, but I may not need to bake it into PoB's implementation
• Automatic token acquisition on 401 error
• Add luasocket license
• Open SimpleGraphic PR for luasocket artifacts
• Server start and timeout messaging/UX

Future goals:

• Secure token storage
• Refresh token usage and storage
• Investigate behavior and QoL with multiple PoB instances open (Access token currently stored in memory, focus PoB window when redirect is made, etc)