little refactoring and cleaner powershell

[osiktech]

little refactoring:

• get latest client from github depending on os architecture
• replace $username and use $env:AppData (installations via RDP will fail otherwise)
• use $env:Temp instead of C:\temp (there are rare cases when windows is not installed on c: plus we already have an environment variable defined for this)
• use $env:ProgramFiles instead of hardcoded path (see $env:Temp)
• use $env:WinDir instead of hardcoded path (see $env:Temp)
• use a function to output ID and Password
• use a variable for content of RustDesk2.toml file
• use a longer password (8 chars is definitely not enough, especially for unattended access)
• cleanup temp files
• try to use native powershell commands Stop-Process instead of "taskkill" and Start-Service instead of "net start"

[dinger1986]

looks good, thanks