feat(txtar): handle quote for gnokey

[gfanton]

Following #1736

This PR updates the gnokey command to better handle quotes within txtar. This is useful for commands like query:

gnokey query vm/qrender --data "gno.land/r/append\n"

The update means gnokey can now handle:
• Arguments in quotes that contain spaces or special characters.
• Escape sequences inside quotes.

See tests for more concrete examples.

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[codecov]

Codecov Report

Attention: Patch coverage is 94.11765% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 44.72%. Comparing base (45c8f90) to head (7eb86e7).

Files	Patch %	Lines
gno.land/pkg/integration/testing_integration.go	94.11%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1745      +/-   ##
==========================================
- Coverage   47.41%   44.72%   -2.70%     
==========================================
  Files         384      456      +72     
  Lines       61187    67543    +6356     
==========================================
+ Hits        29014    30209    +1195     
- Misses      29744    34806    +5062     
- Partials     2429     2528      +99     

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[deelawn]

Great idea for a PR. Looks good to me 👍

[zivkovicmilos]

Thank you for adding good coverage 🙏

[tbruyelle]

LGTM