New Feat: CosmIframe

[hard-nett]

Goal: Add support for CosmIframe: https://github.com/DA0-DA0/cosmiframe

An initial implementation draft can be found here: https://github.com/hard-nett/restake-ui

Implementation

• A new signing provider for CosmIframe is created
• Only when app is being accessed by an Iframe should the CosmIframe feature be an option when connecting wallet
• Bump CosmJS dependencies to ^0.32

[tombeynon]

Thanks again for this! I'll pick this up ASAP