LICENSE: Add Apache 2.0 license file
According to our company licensing policy for software the Yocto layers should be licensed under the Apache 2.0 license. Adapt the LICENSE-2.0.txt file from https://www.apache.org/licenses/LICENSE-2.0.txt as described in the APPENDIX.
Add the license as LICENSE.txt file to the layer repository.
BCS 746-000657
Change-Id: I247b2eb004aea29a13059d6e64bb0bc3d06ee9fe