use native golang SSH library but ssh-keygen when enable built-in SSH server to remove dependent on that command lines

[lunny]

No description provided.

[Nubston]

i don't quite know what lunny meant by making PR to remove dependent on ssh-keygen but i need this fix here that they have done to use the internal ssh server since i get ssh-keygen error on 1.7.1 when trying to use internal server

[codecov-io]

Codecov Report

Merging #5976 into master will increase coverage by <.01%.
The diff coverage is 44.82%.

@@            Coverage Diff            @@
##           master   #5976      +/-   ##
=========================================
+ Coverage    38.7%   38.7%   +<.01%     
=========================================
  Files         330     330              
  Lines       48857   48884      +27     
=========================================
+ Hits        18910   18922      +12     
- Misses      27207   27217      +10     
- Partials     2740    2745       +5

Impacted Files	Coverage Δ
modules/ssh/ssh.go	55.48% <44.82%> (-2.18%)	⬇️

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