Problem: no docs for Keplr setup example

[tomtau]

Given Keplr can support the network out of the box: https://github.com/giansalex/cro-keplr
it may be worth documenting its setup as an additional option under Wallets: https://crypto.org/docs/wallets/ledger.html

Extra challenge for coding samples @aw126 : as it's a web wallet, the setup tutorial could potentially be interactive / show the end results directly on the tutorial page. Not sure if there's already some nice interactive tutorial for Keplr that could be adapted -- @dogemos may know.