Encoding error of `priv_validator_key.json` when sharding for Horcrux

[mazzy89]

Description

In order to increase the security of validator keys, Horcrux comes into help and allow to shard a private validator key making sure blocks can be signed only a set number of shards keys are retrieved. This increases not only the security but also the fault-tolerance of a validator.

Horcrux uses the a package from ComeBFT to encode/decode private key while we use Amino. This makes the creation of the shards from the ED25519 private key failing with an error like:

Error: encoding/hex: invalid byte: U+0067 'g'

when the command is executed.

$ horcrux create-ed25519-shards --chain-id cosmoshub-4 --key-file /path/to/cosmoshub/priv_validator_key.json --threshold 2 --shards 3

How could we have Horcrux setup for a Gnolang chain?

cc @r3v4s @albttx @sw360cab @zivkovicmilos

[moul]

Supporting a horcrux or a similar feature sounds useful, but the core team won't work on it for now.

If members of the community want to contribute, especially those with DevOps skills, please feel free to work on this one.

[mazzy89]

I think DevX team should come here into action and help on this regard. @salmad3 @ilgooz what do you think?