Get-DecryptedObject: Refactor related commands

[andreasjordan]

Get-DecryptedObject needs two things:

• A Dedicated Admin Connection (DAC) to select master.sys.syslnklgns
• A WinRM connection to read "HKLM:\SOFTWARE\Microsoft\Microsoft SQL Server$serviceInstanceId\Security"

That's why Get-DecryptedObject needs $Credential which it used all the time, but the parametr was missing.

So every command that calls Get-DecryptedObject needs $Credential as well. This is:

• Copy-DbaCredential
• Copy-DbaDbMail
• Copy-DbaLinkedServer
• Export-DbaCredential
• Export-DbaLinkedServer

So every command that calls one of those commands needs $Credential as well. This is:

• Start-DbaMigration
• Sync-DbaAvailabilityGroup
• Export-DbaInstance

TODO:

• Sync-DbaAvailabilityGroup allows pipeline input and works only if the used connection is a dac. A test has to be implemented or we have to remove pipeline support. As Sync-DbaAvailabilityGroup has no test this needs to be tested in my lab.

More problems:

• The commands that call Get-DecryptedObject open and close a DAC. But if they are called from other commands or from scripts using an already open DAC, then they must noch close this DAC.
• In Start-DbaMigration, we need a DAC for passwords, but also a non-DAC for Copy-DbaDatabase.

I hope I can solve that nightmare in the next days, but maybe it will take until next weekend.