Add message option extension to signal msg signers

[ryanchristo]

Summary

Ref: https://github.com/regen-network/regen-ledger/pull/1244#issuecomment-1200793875

A new message option extension was added in the v0.46 release, which can be used to mark the expected signer.

An initial attempt to implement resulted in the following error:

regen/ecocredit/v1/tx.proto:284:10:message regen.ecocredit.v1.MsgSend: unknown extension cosmos.msg.v1.signer
regen/ecocredit/v1/tx.proto:329:10:message regen.ecocredit.v1.MsgRetire: unknown extension cosmos.msg.v1.signer
regen/ecocredit/v1/tx.proto:352:10:message regen.ecocredit.v1.MsgCancel: unknown extension cosmos.msg.v1.signer
regen/ecocredit/v1/tx.proto:370:10:message regen.ecocredit.v1.MsgUpdateClassAdmin: unknown extension cosmos.msg.v1.signer

We need to further investigate the issue and then we should add the extension to all messages.

---

For Admin Use

• [ ] Not duplicate issue
• [ ] Appropriate labels applied
• [ ] Appropriate contributors tagged
• [ ] Contributor assigned/self-assigned