Rename webhook and open api urls (#11684)

We want to have fewer base path for routing.

We will have:
- /files
- /webhooks
- /graphql
- /metadata
- /rest
- /auth
- /healthz

I'm moving /open-api under /rest, and centralizing the webhooks
(removing /stripe and /cloudflare)

packages/twenty-front/src/modules/settings/playground/components/PlaygroundSetupForm.tsx

@@ -59,7 +59,7 @@ export const PlaygroundSetupForm = () => {
     try {
       // Validate by fetching the schema (but not storing it)
       const response = await fetch(
-        `${REACT_APP_SERVER_BASE_URL}/open-api/${values.schema}`,
+        `${REACT_APP_SERVER_BASE_URL}/rest/open-api/${values.schema}`,
         {
           headers: { Authorization: `Bearer ${values.apiKeyForPlayground}` },
         },

packages/twenty-front/src/modules/settings/playground/components/RestPlayground.tsx

@@ -68,7 +68,7 @@ export const RestPlayground = ({ onError, schema }: RestPlaygroundProps) => {
         <ApiReferenceReact
           configuration={{
             spec: {
-              url: `${REACT_APP_SERVER_BASE_URL}/open-api/${schema}?token=${playgroundApiKey}`,
+              url: `${REACT_APP_SERVER_BASE_URL}/rest/open-api/${schema}?token=${playgroundApiKey}`,
             },
             authentication: {
               http: {