This makes the account system much more modular
and makes it treat errors as something recoverable,
unless they come directly from the MSA refresh token
becoming invalid.
- We now use the new endpoint for loggiong in via XBox tokens (/launcher/login)
- We now check game entitlements instead of only relying on MC profile presence
- Accounts can now be added even when they do not have a profile
- The launcher will guide you through selecting a Minecraft name if you don't have one yet
