docs: how to revive an expired IBC client

[Reecepbcups]

Request from the interchain discord (parveenkaushik)

We should have a guide similar to https://medium.com/simplystaking/reviving-an-ibc-client-with-governance-hermes-relayer-362a1da4814d

#876 may be an initial reference to help automate this.

Would be nice to auto generate the submit proposal for sdk v45 and 46+ chains. This way 1 command could handle the entire flow to revive for better UX? (just a thought)