Be able to specify front port (#8382)

- Added REACT_APP_PORT in front .env
- Use value if specified otherwise 3001 by default

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

packages/twenty-front/.env.example

@@ -2,6 +2,7 @@ REACT_APP_SERVER_BASE_URL=http://localhost:3000
 GENERATE_SOURCEMAP=false
 
 # ———————— Optional ————————
+# REACT_APP_PORT=3001
 # CHROMATIC_PROJECT_TOKEN=
 # VITE_DISABLE_TYPESCRIPT_CHECKER=true
 # VITE_DISABLE_ESLINT_CHECKER=true