feat: support generate primary and public key for sshd

[sophon-zt]

{{- $key := sshKeyGen }}
PRIVATE_KEY="{{ $key.PrivateKey }}"
PUBLIC_KEY="{{ $key.PublicKey }}"

[apecloud-bot]

This branch name is not following the standards: feature/|bugfix/|release/|hotfix/|support/|releasing/|dependabot/

[codecov]

Codecov Report

Attention: Patch coverage is 73.91304% with 6 lines in your changes missing coverage. Please review.

Project coverage is 62.54%. Comparing base (400d86d) to head (d30bcb9).
Report is 2 commits behind head on main.

Files	Patch %	Lines
pkg/gotemplate/sshkeygenerator.go	72.72%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8001      +/-   ##
==========================================
- Coverage   62.55%   62.54%   -0.02%     
==========================================
  Files         324      325       +1     
  Lines       40221    40244      +23     
==========================================
+ Hits        25161    25170       +9     
- Misses      12762    12772      +10     
- Partials     2298     2302       +4     

Flag	Coverage Δ
unittests	62.54% <73.91%> (-0.02%)	⬇️

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[apecloud-bot]

This branch name is not following the standards: feature/|bugfix/|release/|hotfix/|support/|releasing/|dependabot/

[sophon-zt]

related issue: #8002