Feat: option to add fee payer account

[arnabghose997]

This PR involves allowing users to set an account as FeePayer, as it is needed for the transaction type /osmos.authz.v1beta1.MsgExec to execute.

Reference Issue: #1155

[webmaster128]

Nice start. I think there is some confision with payer vs. granter. Please consult the Cosmos SDK team if you have questions what the difference is. I never used this tech.

[arnabghose997]

payer and granter fields are added as part of StdFee interface.

[webmaster128]

Looks good overall, thanks.

Do you have an idea how to test the new code?

[arnabghose997]

The sequence of transactions for a complete authz+feegrant are as follows:

1. /cosmos.authz.v1beta1.MsgGrant
2. /cosmos.feegrant.v1beta1.MsgGrantAllowance
3. /cosmos.authz.v1beta1.MsgExec

The test should execute the above messages sequentially. We can consider packages/stargate/src/modules/authz/queries.spec.ts as a reference.

Before proceeding with writing this test, I have a query. As mentioned in HACKING.md, we need to run few scripts and set flags to perform complete test suite run. In the current version of HACKING.md present on main branch, there is mention of running launchpad blockchain, although its corresponding scripts aren't present in the main branch. So, I wanted to know about the scipts we need to run and the flags that needs to set instead of launchpad?

[webmaster128]

Sounds good, thank you.

In #1206 I fixed the outdated docs. Let me know if there are any questions left.

[dckc]

Anything I can do to help this along?

[webmaster128]

Anything I can do to help this along?

Thank you @dckc. I am hesitant to merge this without the feature being tested. I don't want this feature to fail in the user's environment. Also having a test case serves as an always up-to-date example how to use the feature. Writing tests may detect flaws in the API. If you could add tests on top of that PR, I think we can get this out.

Please note that on latest main we have Cosmos SDK 0.44 and 0.46 (simapp44/simapp46) test chains. simapp42 was removed. With those chains it should be possible to test the whole flow.

[webmaster128]

I'm finishing this work in #1262. The test is in c959343. Turns out no /cosmos.authz.v1beta1.MsgGrant and /cosmos.authz.v1beta1.MsgExec is needed to test that as you can use feegrant for a simple bank send.