Add Registering a Pool to stake pool documentation (#1066)
* Create register-stake-pool.md * Update sidebars.js replaced register-stake-pool-metadata.md with register-stake-pool.md * formatting and English grammar corrections * Update register-stake-pool.md Added info about case when we need to configure multiple relays * Update register-stake-pool.md minor change, updated description regarding multiple relays --------- Co-authored-by: Robert Phair <[email protected]> Co-authored-by: Jurijs I <[email protected]>