Add LICENSE

[theotchlx]

Problem

lumper is missing a LICENSE file. The SealCI team wants to use lumper's code as the inspiration for its VMM.

SealCI is released under the Apache 2.0 license. This copyright license is permissive and adequately protects contributors.

Suggested solution

I humbly suggest lumper be licensed under the Apache 2.0 license, or a compatible license that fits the needs of the contributors.