Add -AsCredential option for Basic/Form authentication

[Badgerati]

Basic and Form authentication from New-PodeAuthScheme, currently supply username/password parameters to the Add-PodeAuth scriptblock:

New-PodeAuthScheme -Basic | Add-PodeAuth -Name 'Login' -ScriptBlock {
        param($username, $password)
}

In most cases you probably just need a pscredentials object. So this is to add a new -AsCredential switch to New-PodeAuthScheme for Basic/Form authentication only. When supplied, Pode will supply the username and password as a pscredential instead:

New-PodeAuthScheme -Basic -AsCredential | Add-PodeAuth -Name 'Login' -ScriptBlock {
        param($creds)
}