Add support for ssz response to `getLightClientUpdatesByRange`

[nflaig]

As per spec this route needs to support ssz responses but the implementation deviates quite a lot from other routes. See implementation notes for details.

There has been previous work on this in https://github.com/ChainSafe/lodestar/pull/4641 and we might be able to reuse some code from there.

Can additional test our implementation against https://eth-light.xyz/, and other light client routes as well. Might need to set Access-Control-Expose-Headers: Eth-Consensus-Version to make it work with the browser.