added check for administrative privilages

[ItsCOMMANDer]

I added a check for administrative privileges, as dism requires admin privileges so the command might fail if the creation script are run without admin rights.

[ItsCOMMANDer]

it might have grammatical errors because my English isn't the best 😅

[noubar]

only grammatical change you should do is change: 'Must be ran' with 'Must be run'

I see this feature to be useful as it is adding understandable error message. In case of the program has been forgotten to be started as admin.