Pass messages to and from the SGX

Rewriting the from/to as appropriate.

Merge branch 'create_customer_id'

* create_customer_id:
  Create customer_id if it does not exist before we start registration
  Break out CustomerPlan
  Inject BackendSgx per customer

Create customer_id if it does not exist before we start registration

Inject BackendSgx per customer

Instead of being a singleton that represents the entire relationship
with the backend, the object is now per-customer (since any meaningful
method requires a customer anyway for the from JID at least) and can be
delegated to directly from Customer.

Merge branch 'new-signup-credit-card-decline'

* new-signup-credit-card-decline:
  Block repeated declines for 24 hours
  Handle credit card decline

Block repeated declines for 24 hours

Merge branch 'new-signup-add-credit-card'

* new-signup-add-credit-card:
  Happy path for credit card signup
  Panic should work on any value for error
  Allow getting default payment method, not just index
  Object representing the backend SGX to use
  Stop polluting Object namespace with Blather DSL
  Work in the presence of em-synchrony
  Helper to allow ordering phone number from Bandwidth v2
  Helper to get a promise that resolves after N seconds
  Every payment kind will need the plan, so put it at the top
  Use registration pattern for Payment kinds
  Method to bill the plan of a Customer
  Use Forwardable for simple delegations
  Helper to allow using sync-style code in a Promise context
  New signup: go to web to choose credit card
  OOB helper
  Reject promise on stanza error
  Fix typo

Happy path for credit card signup

Assuming credit card payment works, you can now activate a new account by paying
with one.

Panic should work on any value for error

Stop polluting Object namespace with Blather DSL

New signup: go to web to choose credit card

This step, if chosen, directs the user to the jmp-pay webapp to add a credit
card.  It includes an OOB element for use by user agents that can handle
that (possibly for webview embed, etc) with a note-based fallback as per XEP.
Once the user chooses "next" the code checks if they have actually added a card,
and if so continues to a yet-unimplemented step and if not repeats the
instruction to go to the web app.

Reject promise on stanza error

Merge branch 'register-command-first-pass'

* register-command-first-pass:
  Add sourcehut CI
  Add Rakefile to run all tests
  Initial registration flow for Bitcoin
  Registrations that start on the web will have a tel selected already
  Helpers for doing Electrum RPC
  Add helper to fetch current BTC sell prices
  Allow skipping tests without being caught in pry

Initial registration flow for Bitcoin

This is the Bitcoin "happy path" where there is already a tel and a customer_id.
Gets all the way to generating a BTC address for payment and quoting an amount.
Stubs out flows for credit card and activation code as well, but does not
implement those flows.

TBD: after bitcoin payment comes in and jmp-pay activates the account, we should
come back here to actually buy the number, select a new one if no longer
available, etc.

Split logic out into testable objects

Rubocop clean. Good test coverage of helper objects.

Currency aware

Look up the user's plan to find out what currency to charge them in.

Submit for settlement

We'd like to actually get the money, not just be allowed to.

Rubocop fixes

Always show money with two decimal places

Only ask which card to use if there is more than one