Adding recover wal tools

[ggarri]

• [ ] Updated all relevant documentation in docs
• [ ] Updated all code comments where relevant
• [ ] Wrote tests

[EnchanterIO]

Hmmm, I think is not the best idea to store 40MB binaries in a github repo. It' better to build it locally from source code, when necessary no?

https://github.com/tendermint/tendermint/blob/master/scripts/json2wal/main.go

or do you have any particular reason to do so?