feat(install.sh): support federated install (#2752)

* feat(install.sh): support federated install

This allows to support federation by exposing:

- FEDERATED: true/false to share the instance
- FEDERATED_SERVER: true/false to start the federated load balancer (it
  forwards requests to the federation)

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* docs: update installer parameters

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

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Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Dave <dave@gray101.com>