WIP: Multi-coins support for validators

[RiccardoM]

Description

This PR should implement the support for multi-coins chains that want to allow validators to support multiple coins denominations during the related operations (delegation, rewards, etc.).

closes: #4783

Checklist

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.
• Wrote tests
• Updated relevant documentation (docs/)
• Added a relevant changelog entry: clog add [section] [-t <tag>] [-m <msg>]
• Re-reviewed Files changed in the github PR explorer

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For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[fedekunze]

I'm against these changes. Extending x/staking to have multiple bond token denoms as this PR is doing is very general. This needs to be extremely specified on an ADR first, as these changes could have security implications.

[RiccardoM]

@fedekunze Thank you for taking the time to help me suggesting what to do! Do you have an example of a previous ADR? I would love to take it as example in order to write the one for this implementation!

[fedekunze]

Sure @RiccardoM. Check here for the general structure. Previous ADRs are located here. There are other ADRs with PRs open, for eg #4732, #4737 and #4780

[alexanderbez]

Why don't we just use sdk.Coin instead of multiple coins?

[RiccardoM]

@alexanderbez I thought that since I was editing that code, I could implement multiple coins. The single coin will then just be a trivial usage of the multiple ones.

[alexanderbez]

@alexanderbez I thought that since I was editing that code, I could implement multiple coins. The single coin will then just be a trivial usage of the multiple ones.

I don't imagine we'll support staking multi-coins anytime soon.

[fedekunze]

The single coin will then just be a trivial usage of the multiple ones.

You'd have to account for minting (which od the staking coins will you mint every block)? Same applies to slashing. Also, I don't know if tendermint supports multiple coins?

[alexanderbez]

Tendermint only cares about power.

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.