Please add LICENSE file

[HavenDV]

Hello. Since, according to laws and also github rules, repositories without a license can only be viewed, it would be great to include an explicit license. Link: https://opensource.stackexchange.com/questions/1720/what-can-i-assume-if-a-publicly-published-project-has-no-license

P.S. I saw the license in the workload folder, and I think the main problem here is with samples, and perhaps it is worth moving the license to the root and marking a separate license for samples

[JoonghyunCho]

@HavenDV Thanks for pointing that out.