Update Get-DellWarranty.psm1

[rpertusio]

Largest changes are:

• Return a PS Object. This is useful when taking the output and manipulating it in a parent script. Example: $output = Get-DellWarranty -ServiceTag $PC -ReturnOjb -Full
• Warranty entitlements are not always in order from Dell. (Example: 4 entitlements for a device, but the 3rd one in the list is the latest.) I added sorting and 'First' / 'Last' picking from the list