Remove net-ssh gem

What does this MR do?

Remove net-ssh gem, which was unintentionally introduced explicitly (!1902 (merged)), but has been not used ever.

Are there points in the code the reviewer needs to double check?

No.

• Note: fog-core removed explicit net/ssh/net/scp dep and came to has implicit dep in 1.33.0 https://github.com/fog/fog-core/pull/166.

Why was this MR needed?

To make gitlab compact.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests
  • [n/a] Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #34867 (closed)