feat: add sshd (script for Windows, docs for mac / linux)

[coolaj86]

• needs README
• needs ~/.local/bin/sshd-service-install
  (like brew-update-service-install, and ~/.local/bin/dashd-hd-service-install)
• needs install.sh testing for sshd and showing message already installed like git, fish, vim

Get-WindowsCapability -Online | Where-Object Name -like 'OpenSSH*'
Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
Start-Service sshd
Set-Service -Name sshd -StartupType 'Automatic'
net user 'user' 'password'

The Firewall may need to be modified:

New-NetFirewallRule -Name sshd -DisplayName 'OpenSSH Server (sshd)' -Enabled True -Direction Inbound -Protocol TCP -Action Allow -LocalPort 22

Or

if (!(Get-NetFirewallRule -Name "OpenSSH-Server-In-TCP" -ErrorAction SilentlyContinue | Select-Object Name, Enabled)) {
    Write-Output "Firewall Rule 'OpenSSH-Server-In-TCP' does not exist, creating it..."
    New-NetFirewallRule -Name 'OpenSSH-Server-In-TCP' -DisplayName 'OpenSSH Server (sshd)' -Enabled True -Direction Inbound -Protocol TCP -Action Allow -LocalPort 22
} else {
    Write-Output "Firewall rule 'OpenSSH-Server-In-TCP' has been created and exists."
}