Added a new atomic to T1202

[NagaSivaGunturu]

Details:
Added a new atomic to T1202, name of the atomic is "Arbitrary file download using the Notepad++ GUP.exe binary"

Testing:
Tested successfully in atomic lab locally

[clr2of8]

Welcome, as this is your first contribution and we hope for more to come, please see some minor adjustment requests below:

• We would like to see this added under T1105 Ingress Tool Transfer instead
• Please mv GUP files from src into bin, since they are mostly binary files
• Maybe change "Mention the directory where GUP.exe & it's dependecies exists exists" to "The directory where GUP.exe & it's dependecies exists"
• The cleanup commands should be able to be rerun multiple times in a row without generating errors due to files already being deleted