Re-enable dropped smarty5 modifier 'abs'

[Matt5K]

There is a smarty modifier used in a template the is not supported in smarty5 -> 'abs' <- found in org.project60.banking/templates/CRM/Banking/PluginImpl/Matcher/Membership.suggestion.tpl lines 63 and 92.
Should it be re-enabled like the modifier "range" (#468)?

Meanwhile i patched it in org.project60.banking/banking.php line 35

/**
 * Implementation of hook_civicrm_config
 */
function banking_civicrm_config(&$config) {
+  if (!isset(CRM_Core_Smarty::singleton()->registered_plugins["modifier"]["abs" ])) {     
+      CRM_Core_Smarty::singleton()->registerPlugin('modifier', 'abs', 'abs');      
+ }
  _banking_civix_civicrm_config($config);
}

[dontub]

Yes, that makes sense. Can you make a PR?

[ufundo]

Given the modifier is only used in two places, I think we can easily refactor to avoid the need for it: #502