Add Keplr v2 sample wallet

[solardiz]

Add Keplr v2 sample wallet from the file attached in https://github.com/openwall/john/issues/5481#issuecomment-2121116722

Since we currently have the Keplr wallet sample files right in the Keplr_Wallet directory (multiple files corresponding to just one wallet), v2 can be added nearby as Keplr2_Wallet or subdirectories need to be created and files moved in there.

We're not going to add support for this wallet soon (and maybe never), but it's good to have the sample recorded where appropriate.

@akirayamaoka32 Please feel free to contribute this via a pull request. Thank you!