Updating AspNetCore sample token handling based on updated security g…

…uidance

Create Governance.ExternalSharingTimer.yml

Added YAML file so that this tool can be pulled into the Office and M365 resource galleries automatically (https://developer.microsoft.com/en-us/office/gallery)

Updated sample YAML description

Create Core.CDNManager.yml

Added YAML file so that this tool can be pulled into the Office and M365 resource galleries automatically (https://developer.microsoft.com/en-us/office/gallery)

Create Core.CDNManager.yml

Added YAML file so that this tool can be pulled into the Office and M365 resource galleries automatically (https://developer.microsoft.com/en-us/office/gallery)