feat: handle transactions through Safe app

[Sekhmet]

Summary

This PR changes three things when executing actions through Safe.

1. When doing any action on EVM spaces (voting, proposing, editing settings) UI will not be blocked and you will be asked to confirm transaction in Safe app.
2. When voting or proposing on Starknet spaces UI will not be blocked and you will be asked to confirm transaction in Safe app and also have access to hash-verifier.

Closes: https://github.com/snapshot-labs/workflow/issues/292

How to test

1. On offchain spaces you can vote and propose and edit settings via Safe.
2. On onchain EVM space you can vote, propose, and edit settings via Safe (non blocking, no hash-verifier link).
3. On onchain Starknet space you can vote and propose via Safe (non blocking, hash-verifier link).

Screenshots

Wasn't sure about design on this screen or text to use there, so I'm open for suggestions.

[pscott]

I think it would make sense to have support for propose and updateSettings, basically any action that requires going back and forth between snapshot and safe :)

[bonustrack]

How is the flow with Snapshot offchain? Would be great to have similar modals

[Sekhmet]

Should be ready for review.