[3006.x] auto discovery of ssh, scp and ssh-keygen binaries.

[ctrix]

What does this PR do?

What issues does this PR fix or reference?

Fixes: #66204

Previous Behavior

salt-ssh was using aliased scripts when running ssh, scp and ssh-keygen

New Behavior

ssh, scp and ssh-keygen paths are discovered and the original ssh binaries are used.

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

Commits signed with GPG?

Yes

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[twangboy]

Hey, @ctrix , this looks great. Would you mind writing a test case and a changelog for this?

[dwoz]

Should this go into 3006.x?

[welcome]

Congratulations on your first PR being merged! 🎉