Client - display page error if can not fetch app config

fittrackee_client/src/locales/en/api.json

@@ -2,6 +2,7 @@
   "ERROR": {
     "UNKNOWN": "Error. Please try again or contact the administrator.",
     "Invalid credentials": "Invalid credentials.",
+    "Network Error": "Network Error",
     "Password and password confirmation don't match": "Password and password confirmation don't match.",
     "Password: 8 characters required": "Password: 8 characters required.",
     "Username: 3 to 12 characters required": "Username: 3 to 12 characters required.",

fittrackee_client/src/locales/en/error.json

@@ -1,5 +1,6 @@
 {
   "UNKNOWN": "Error. Please try again or contact the administrator.",
+  "APP_ERROR": "The application seems encounter some issues.<br />Please try later or contact the administrator.",
   "NOT_FOUND": {
     "PAGE": "Page not found"
   }

fittrackee_client/src/locales/fr/api.json

@@ -2,6 +2,7 @@
   "ERROR": {
     "UNKNOWN": "Erreur. Veuillez réessayer ou contacter l'administrateur.",
     "Invalid credentials": "Identifiants invalides.",
+    "Network Error": "Erreur Réseau",
     "Password and password confirmation don't match": "Les mots de passe saisis sont différents.",
     "Password: 8 characters required": "8 caractères minimum pour le mot de passe.",
     "Username: 3 to 12 characters required": "3 à 12 caractères requis pour le nom.",

fittrackee_client/src/locales/fr/error.json

@@ -1,5 +1,6 @@
 {
   "UNKNOWN": "Erreur. Veuillez réessayer ou contacter l'administrateur.",
+  "APP_ERROR": "L'application semble rencontrer quelques problèmes.<br />Veuillez réessayer plus tard ou contacter l'administrateur.",
   "NOT_FOUND": {
     "PAGE": "Page introuvable"
   }