Create `Head` method

[tzdybal]

Head method (corresponding to /head endpoint) needs to be added to client.

Specs: https://docs.celestia.org/developers/node-api/#get-head
Code in node: https://github.com/celestiaorg/celestia-node/blob/0466d9c9222f7ceacba2223a83fd352b5d751d1e/service/rpc/header.go#L22

This is height-less version of /header endpoint.

[Regis-Caelum]

Hey @tzdybal i would like to take this one up

[tzdybal]

Great! 🎉

Feel free to ask any questions.

[Regis-Caelum]

what would be the response type for head request, no implementation is mentioned

[Regis-Caelum]

Great! tada

Feel free to ask any questions.

Hey, what would be the response type for head request, no implementation is mentioned