Move osmoutils into own mod

[nicolaslara]

What is the purpose of the change

#3771 started moving some of our tools to their own modules. This PR expands that by moving osmoutils.

Both of these are a requirement for #3747

Brief Changelog

(for example:)

• Move osmoutils into its own go.mod. To update, change your osmoutils import from github.com/osmosis-labs/osmosis/v13/osmoutils to github.com/osmosis-labs/osmosis/osmoutils
• Moved osmoassert to osmoutils
• Fix Exp2 tests to use assets from osmoutils

Testing and Verifying

All tests still pass

Documentation and Release Note

• Does this pull request introduce a new feature or user-facing behavior changes? (yes / no)
• Is a relevant changelog entry added to the Unreleased section in CHANGELOG.md? (yes / no)
• How is the feature or change documented? (not applicable / specification (x/<module>/spec/) / Osmosis docs repo / not documented)

[nicolaslara]

For reference, this is how to get the version string if we want to avoid the replaces:

TZ=UTC git --no-pager show \
  --quiet \
  --abbrev=12 \
  --date='format-local:%Y%m%d%H%M%S' \
  --format="%cd-%h"

[ValarDragon]

Closing for #3827 due to conflicts I made in interrim