refactor: generalize ibc-testkit types to allow remote storage and light clients

[rnbguy]

Closes: #1269

Description

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PR author checklist:

• Added changelog entry, using unclog.
• Added tests.
• Linked to GitHub issue.
• Updated code comments and documentation (e.g., docs/).
• Tagged one reviewer who will be the one responsible for shepherding this PR.

Reviewer checklist:

• Reviewed Files changed in the GitHub PR explorer.
• Manually tested (in case integration/unit/mock tests are absent).

[codecov]

Codecov Report

Attention: Patch coverage is 97.14286% with 6 lines in your changes missing coverage. Please review.

Project coverage is 67.49%. Comparing base (7ff41b3) to head (9236182).

Files	Patch %	Lines
ibc-testkit/src/relayer/context.rs	86.20%	4 Missing ⚠️
ibc-testkit/src/testapp/ibc/core/types.rs	71.42%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1270      +/-   ##
==========================================
+ Coverage   67.42%   67.49%   +0.06%     
==========================================
  Files         235      235              
  Lines       23811    23883      +72     
==========================================
+ Hits        16055    16120      +65     
- Misses       7756     7763       +7     

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