support base64 string for certificate

[mouki9]

In the readme now states that the PowerShell needs to be edited whenever using cloud agent.
The same logic can be used as in the part of the AccessToken.
Use the variable $certificateBase64 to determine what you need to do.
Possible solution could be:
if (-not[string]::IsNullOrEmpty($certificateBase64)) {
$dataset = $datasetJson.content | ConvertFrom-Json
}
elseif (-not [string]::IsNullOrEmpty($certificatePathertificatePath)) {
$datasetCorrected = [Text.Encoding]::UTF8.GetString([Text.Encoding]::GetEncoding(28591).GetBytes($datasetJson.content))
$dataset = $datasetCorrected | ConvertFrom-Json
}
else {
Throw "No certificate configured"
}

please test and verify