Refactor command list to use composition

Also rename buy credit to top up

Command to get to the credit card settings page

Reply to extdisco with sip server

Spec says we must reply to all IQs

So say feature-not-implemented if we haven't got it with some other handler.

Merge identical cases

Validate that amount of credit to buy is in valid range

Rename buy-credit to buy credit

Merge branch 'conditionally-show-commands'

* conditionally-show-commands:
  Only show buy credit option if customer has a plan and a credit card
  Show commands conditionally (plus add voicemail record command)

Show commands conditionally (plus add voicemail record command)

Refactor to a factory that allows commands to be shown conditionally, so that
the voicemail record command can only be shown if the customer has a forwarding
target set up.

Merge branch 'tel-search-temp'

* tel-search-temp:
  No tel picker yet, so just go to the webpage

Use before filter to actually come before everything

Otherwise we go in hierarchy order and stanza comes last.

Merge branch 'passthrough-commands'

* passthrough-commands:
  Pass through commands we know the SGX can handle
  Pass everything from SGX to user, not just <message/>
  Remove some of the noise from the command list

Pass through commands we know the SGX can handle

Pass everything from SGX to user, not just <message/>

Remove some of the noise from the command list

Fix copy-paste error

These lines won't work because not processing an iq or anything with a node
here.  Set up sentry in a sensible way for messages.

No tel picker yet, so just go to the webpage

Direct users to the homepage if they haven't selected a tel yet.  Not what we
want eventually, but better than crashing.

Merge branch 'create-reset-sip-account'

* create-reset-sip-account:
  Create or reset SIP account
  Factor out Catapult connection

Create or reset SIP account

New command to create or reset SIP account.  Always try create first because
it's faster and more common, fall back to search the list for our account if
that fails due to conflict.  Password is always randomly generated from the
mnemonicode word list.

Usage command

Customer has a CustomerUsage which can fetch data to build a UsageReport
which returns a jabber:x:data form "table" as per spec for per-day in
the last month.

Minutes come from cdr table in postgresql.
Messages come from redis.