refactor(x/data): consistent use of content hash

[ryanchristo]

Description

Closes: #1006

This pull request applies consistent use of content_hash and content_hashes in the data module.

---

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)

[technicallyty]

lgtm

[aleem1314]

I think we can delete this file. We are not using genesis types.

[ryanchristo]

700eefc

[aleem1314]

lgtm

[codecov]

Codecov Report

Merging #1014 (c1e6ae9) into master (470f881) will decrease coverage by 0.11%.
The diff coverage is 83.60%.

@@            Coverage Diff             @@
##           master    #1014      +/-   ##
==========================================
- Coverage   60.09%   59.98%   -0.12%     
==========================================
  Files         217      216       -1     
  Lines       23212    23186      -26     
==========================================
- Hits        13950    13908      -42     
- Misses       7973     7992      +19     
+ Partials     1289     1286       -3     

Flag	Coverage Δ
experimental-codecov	59.98% <83.60%> (-0.02%)	⬇️
stable-codecov	?

Flags with carried forward coverage won't be shown. Click here to find out more.