Minimun version of PaymentShared (mjwshared) is 1.2.3

• Fix #8 Can't update billing details.
• Fix #14 Unable to load membership renewal form on back end.
• Towards #5:
  • See !13
  • Convert mandates table to SmartdebitMandate entity. Add refresh_date field.
  • Refresh the oldest 100 mandates during nightly sync job.
• Switch to using contributionrecur.processor_id instead of deprecated contributionrecur.trxn_id.
• Convert various sync functions to API4.
• Switch most mandate functions to use API.
• Set min version of mjwshared to 1.2.3
• Convert checks class to non-static to match other extensions.
• Fix doPayment return params.
• Fix tests.
• Fix loading of smartdebit mandate details when using test processor.