refactor: Move to x/tx package

[amaury1093]

Description

ref: #14600

Simply move the contents of tx/ to x/tx.

In follow-ups, whenever it's useful we should:

• move parts to types/tx and x/auth/tx to x/tx when interesting, and when they don't depend on the root sdk
• create aliases on root sdk to keep backwards-compatibility

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[julienrbrt]

This needs to be updated https://github.com/cosmos/cosmos-sdk/blob/94c2aff/.github/workflows/test.yml#L562-L590.
Could you go through this list: #14221?

[alexanderbez]

types/tx and x/auth/tx to x/tx when interesting

Is there any reason why not do this now? Unless they depend on the SDK...?

[amaury1093]

Unless they depend on the SDK...?

Yeah, quite heavily. I'll try to untangle those in follow-ups.

[amaury1093]

@julienrbrt I think the checklist is done now, see c67abd0

[julienrbrt]

A PR adding a new vanity url must be created here: https://github.com/cosmos/vanity.
We should possibly bundle the addition of x/nft and x/circuit there too.

[amaury1093]

cosmos/vanity#32

[julienrbrt]

lgtm!

[julienrbrt]

One tiny nit: changing the path here too https://github.com/cosmos/cosmos-sdk/blob/94c2aff/go.work.example#L13

[likhita-809]

lgtm