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

- remove subscription model
- remove billing-related code

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

@@ -1,19 +0,0 @@
-{
-  "BILLING": {
-    "HEADER": "Facturatie",
-    "LOADING": "Ophalen Abonnementen",
-    "ACCOUNT_STATE": "Accountstatus",
-    "AGENT_COUNT": "Aantal Medewerkers",
-    "PER_AGENT_COST": "Kosten per medewerker",
-    "TOTAL_COST": "Totale kosten",
-    "BUTTON": {
-      "ADD": "Betaalmethode toevoegen",
-      "EDIT": "Betalingsmethode bewerken"
-    },
-    "TRIAL": {
-      "TITLE": "Uw proefperiode is voorbij",
-      "MESSAGE": "Voeg een betaalmethode toe om Chatwoot te blijven gebruiken."
-    },
-    "ACCOUNT_LOCKED": "Uw account is op dit moment niet beschikbaar. <br>Neem contact op met uw beheerder voor heractivatie."
-  }
-}

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

@@ -102,7 +102,6 @@
     "AGENTS": "Medewerkers",
     "INBOXES": "Inboxen",
     "CANNED_RESPONSES": "Standaard antwoorden",
-    "BILLING": "Facturatie",
     "INTEGRATIONS": "Integraties",
     "ACCOUNT_SETTINGS": "Accountinstellingen"
   }