Chore: Remove dead code related to billing (#935)

- remove subscription model
- remove billing-related code

app/javascript/dashboard/i18n/locale/ca/billing.json

@@ -1,19 +0,0 @@
-{
-  "BILLING": {
-    "HEADER": "Facturació",
-    "LOADING": "S'estan obtenin les suscripcions",
-    "ACCOUNT_STATE": "Estat del compte",
-    "AGENT_COUNT": "Compte d'agent",
-    "PER_AGENT_COST": "Per cost d'agent",
-    "TOTAL_COST": "Cost total",
-    "BUTTON": {
-      "ADD": "Afegir mètode de pagament",
-      "EDIT": "EDITAR Mètode de pagament"
-    },
-    "TRIAL": {
-      "TITLE": "S'ha acabat el període de prova",
-      "MESSAGE": "Afegiu un mètode de pagament per continuar utilitzant Chatwoot."
-    },
-    "ACCOUNT_LOCKED": "El seu compte no està disponible de moment. <br>Poseu-vos en contacte amb l'administrador per reactivar-lo."
-  }
-}

app/javascript/dashboard/i18n/locale/ca/index.js

@@ -1,6 +1,5 @@
 /* eslint-disable */
 import { default as _agentMgmt } from './agentMgmt.json';
-import { default as _billing } from './billing.json';
 import { default as _cannedMgmt } from './cannedMgmt.json';
 import { default as _chatlist } from './chatlist.json';
 import { default as _contact } from './contact.json';
@@ -17,7 +16,6 @@ import { default as _generalSettings } from './generalSettings.json';
 
 export default {
   ..._agentMgmt,
-  ..._billing,
   ..._cannedMgmt,
   ..._chatlist,
   ..._contact,

app/javascript/dashboard/i18n/locale/ca/settings.json

@@ -87,7 +87,6 @@
     "AGENTS": "Agents",
     "INBOXES": "Safates d'entrada",
     "CANNED_RESPONSES": "Respostes Predeterminades",
-    "BILLING": "Facturació",
     "INTEGRATIONS": "Integracions",
     "ACCOUNT_SETTINGS": "Configuració del compte"
   }