feat: Add split-view component

[gethinwebster]

Description

Related links, issue #, if available: n/a

How has this been tested?

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.13%. Comparing base (5f1e362) to head (5a23765).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4080   +/-   ##
=======================================
  Coverage   97.12%   97.13%           
=======================================
  Files         864      868    +4     
  Lines       25327    25411   +84     
  Branches     9141     9165   +24     
=======================================
+ Hits        24599    24682   +83     
- Misses        681      723   +42     
+ Partials       47        6   -41     

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