Add OpenSSH client package to linux community-stable images

[kiazhi]

PR Summary

1. Addresses Enhancement request: Add ssh to images #374 enhancement request for community-stable images.

In order to use Enter-PSSession to connect with other (Windows or Linux) VM and Container, OpenSSH client package is required.

Below is the list of OpenSSH client package required for various linux distros:

• openssh-clients package for Amazon Linux
• openssh package for ArchLinux
• openssh package for BlackArch
• openssh-client package for ClearLinux
• openssh-client package for KaliLinux
• openssh-clients package for Oracle Linux
• openssh-client package for ParrotSec
• openssh-clients package for Photon

2. Remove the need of wget package and use curl to download PowerShell package instead.

3. Other minor fixes

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Change is not breaking
• Make sure all Dockerfile, .sh, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.
• Adds a new image or tag
  • Not Applicable
• OR
  • Update README.powershellcommunity.md
  • Update vsts-ci.yml

[kiazhi]

Found ArchLinux and BlackArch in community-stable are having build issues due to ArchLinux's changes to the *.xz old file extension to *.zst new file extension due to updates rolling out.

https://www.archlinux.org/news/now-using-zstandard-instead-of-xz-for-package-compression/

Arch Linux - News: Now using Zstandard instead of xz for package compression