[Epic]: Remove legacy params subspace from module

[julienrbrt]

Summary

In v0.47, all SDK modules migrated to store their own parameters and x/params has been deprecated.
There was a module wide migration to do this, which added a hard dependency on params.

Problem Definition

That migration added a hard dependency on x/params for all core modules that had params.

• cosmos-sdk/x/bank/module.go

  Lines 95 to 104 in 9bc84c9

  	// AppModule implements an application module for the bank module.
  	type AppModule struct {
  	AppModuleBasic
  	keeper keeper.Keeper
  	accountKeeper types.AccountKeeper
  	// legacySubspace is used solely for migration of x/params managed parameters
  	legacySubspace exported.Subspace
  	}

• cosmos-sdk/x/bank/exported/exported.go

  Lines 15 to 25 in 9bc84c9

  	type (
  	ParamSet = paramtypes.ParamSet
  	// Subspace defines an interface that implements the legacy x/params Subspace
  	// type.
  	//
  	// NOTE: This is used solely for migration of x/params managed parameters.
  	Subspace interface {
  	GetParamSet(ctx sdk.Context, ps ParamSet)
  	}
  	)

Given the SDK policy to support the in-place migrations for the last two major versions (https://docs.cosmos.network/main/migrations/intro), we can now remove those migrations and the legacy params subspace from all modules from v0.51.

Work Breakdown

• auth
• bank
• crisis
• distribution
• gov
• mint
• slashing
• staking
• Update UPGRADING.md (make clear that chains migrating to v0.51 must have migrated to v0.47 or v0.50 before. Mention as well that it leads to some API break, but people using depinject won't notice anything).

[tac0turtle]

should we spin params into its own go.mod as well?

[julienrbrt]

should we spin params into its own go.mod as well?

I cannot find @kocubinski's dep graph issue, but I think we should if possible.

[alexanderbez]

Thanks @julienrbrt. ACK on removing these migrations and x/params deps

[tac0turtle]

it seems we have to remove the migrations as well, is this what you were expecting?

[alexanderbez]

Yes, that's exactly the goal

[kocubinski]

@julienrbrt here it is #13012