feat: generate secret function and replaced few instances (#7810)

This PR fixes #4588

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Co-authored-by: Félix Malfait <felix@twenty.com>
Co-authored-by: Charles Bochet <charles@twenty.com>

render.yaml

@@ -18,13 +18,7 @@ services:
         name: server
         type: web
         envVarKey: RENDER_EXTERNAL_URL
-    - key: ACCESS_TOKEN_SECRET
-      generateValue: true
-    - key: LOGIN_TOKEN_SECRET
-      generateValue: true
-    - key: REFRESH_TOKEN_SECRET
-      generateValue: true
-    - key: FILE_TOKEN_SECRET
+    - key: APP_SECRET
       generateValue: true
     - key: PG_DATABASE_HOST
       fromService:
@@ -55,13 +49,7 @@ services:
         name: server
         type: web
         envVarKey: RENDER_EXTERNAL_URL
-    - key: ACCESS_TOKEN_SECRET
-      generateValue: true
-    - key: LOGIN_TOKEN_SECRET
-      generateValue: true
-    - key: REFRESH_TOKEN_SECRET
-      generateValue: true
-    - key: FILE_TOKEN_SECRET
+    - key: APP_SECRET
       generateValue: true
     - key: PG_DATABASE_HOST
       fromService: