Implement an lnbits API module

[chrislennon]

This starts the approach of using a js module for lnbits api.

• Moves over the create user (and initial wallet) command to use this
  • /create @user
• Implements first helper function of 'create if not exist' for user wallet
• Adds command for getting users balance (user will only have 1 wallet currently)
  • /balance @user
• Adds invoice creation command optionally for another user (Image below)
  • /payme [amount] [description] @user
  • Now with added QR!
  • With (temporarily non functional) 'Pay Now' action button

• Added basic tipping command (forces creation and payment of invoices)