Secure Connect - OOB & Passkey

[unknownconstant]

This will also require

• [x] a method to set the IO Capabilities
• [x] Implementation of the different methods to be used in Phase 2
  • [x] Just Works
  • [x] Numeric Comparison
  • [ ] Passkey Entry
  • [ ] Out Of Band (OOB)

Originally posted by @eltos in https://github.com/unknownconstant/ArduinoBLE/issues/9#issuecomment-754112371