Abstract bitpayCardCredentials to appIdentity. Improve alert text on card removal.

src/js/services/appIdentityService.js

@@ -0,0 +1,34 @@
+'use strict';
+
+angular.module('copayApp.services').factory('appIdentityService', function($log, lodash, storageService, bitauthService) {
+  var root = {};
+
+  root.getIdentity = function(network, cb) {
+    var pubkey, sin, isNew;
+    storageService.getAppIdentity(network, function(err, data) {
+      if (err) return cb(err);
+      if (lodash.isString(data)) {
+        data = JSON.parse(data);
+      }
+      var appIdentity = data || {};
+      if (lodash.isEmpty(appIdentity) || (appIdentity && !appIdentity.priv)) {
+        isNew = true;
+        appIdentity = bitauthService.generateSin();
+      }
+      try {
+        pubkey = bitauthService.getPublicKeyFromPrivateKey(appIdentity.priv);
+        sin = bitauthService.getSinFromPublicKey(pubkey);
+        if (isNew)
+          storageService.setAppIdentity(network, JSON.stringify(appIdentity), function(err) {});
+      }
+      catch (e) {
+        $log.error(e);
+        return cb(e);
+      };
+      return cb(null, appIdentity);
+    });
+  };
+
+  return root;
+  
+});