Add decentralized-internet package (#15129)

* Create package.py

* Update package.py

* Update package.py

* Update package.py

* Update package.py

* Update var/spack/repos/builtin/packages/decentralized-internet/package.py

Commit suggestion

Co-Authored-By: Adam J. Stewart <ajstewart426@gmail.com>

* Update package.py

Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>

var/spack/repos/builtin/packages/decentralized-internet/package.py

+# Copyright 2013-2020 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class DecentralizedInternet(MakefilePackage):
+    """A library for building decentralized and grid computing projects"""
+    homepage = "https://lonero.readthedocs.io"
+    url      = "https://github.com/Lonero-Team/Decentralized-Internet/releases/download/4.2.3/Decentralized.Internet.tar.gz"
+    maintainers = ['Lonero-Team', 'Mentors4edu']
+    version('4.2.3', sha256='2922b9128b411ece2f04d07942a453f1e772548aa27b3936c9f9bcfbc0737058')