testing/qrtr: new aport

qrtr is a dependency of hexagonrpcd 0.3 and newer, which is currently packaged in community and temporarily stuck at 0.1 until qrtr is packaged in Alpine. This PR packages qrtr for Alpine, it previously resided in PostmarketOS' pmaports. I have explicit permission from the maintainer in pmaports to take over maintainership and submit this MR to aports and am willing to commit to updating and maintaining it in the future. A follow-up MR will update hexagonrpcd and move this to community.