feat: add support to display mnemonic discreetly for `algokey import` and `algokey export`

[Halimao]

Summary

Similar to #5886

Refer to comment, this pr is for algokey import and algokey export

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 14.28571% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 55.68%. Comparing base (e1db9e1) to head (20fe899). Report is 34 commits behind head on master.

Files	Patch %	Lines
cmd/algokey/export.go	14.28%	6 Missing :warning:
cmd/algokey/import.go	14.28%	6 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5932      +/-   ##
==========================================
- Coverage   55.71%   55.68%   -0.03%     
==========================================
  Files         487      487              
  Lines       68048    68060      +12     
==========================================
- Hits        37911    37898      -13     
- Misses      27572    27597      +25     
  Partials     2565     2565              

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[Halimao]

@gmalouf Hi sir, could u plz help me review this PR, since it's similar to PR #5886 and this new feature won't take effect by default

[Halimao]

@algorandskiy Hi sir, could u plz help me review this pr~

[gmalouf]

Hi there,

We've discussed this as a team, and decided not to move forward here. Further we just merged #5974, which reverts #5886.

As part of a review of our external dependencies (in the wake of the xz incident), we decided the sensitivity of this data was not worth the risk inherent in post-processing it with this external library.

Best of luck with your further work.

Algorand Team