Add ADF (#14423)

* Add ADF

* Fix typo and lint

* fix lint again

* one more lint fix

* fix identation

* still stying to fix identation

* one final fix

* import needed libraries

* changes as per reviewer's request

fix setup environment function, enhance recipe

* add import os once again

* chnages as per reviewer's request

var/spack/repos/builtin/packages/adf/package.py

+# Copyright 2013-2019 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 *
+import os
+
+
+class Adf(Package):
+    """Amsterdam Density Functional (ADF) is a program for first-principles
+    electronic structure calculations that makes use of density functional
+    theory."""
+
+    homepage = "https://www.scm.com/product/adf/"
+    version('2017.113', '666ef15d253b74c707dd14da35e7cf283ca20e21e24ed43cb953fb9d1f2f1e15')
+
+    def url_for_version(self, version):
+        return "file://{0}/adf/adf{1}.pc64_linux.openmpi.bin.tgz".format(
+               os.getcwd(), version)
+
+    # Licensing
+    license_required = True
+    license_files = ['license.txt']
+    license_vars = ['SCMLICENSE']
+
+    def setup_run_environment(self, env):
+        env.set('ADFHOME', self.prefix)
+        env.set('ADFBIN', self.prefix.bin)
+        env.set('ADFRESOURCES', self.prefix.atomicdata)
+        env.set('SCMLICENSE', join_path(self.prefix, 'license.txt'))
+        env.set('SCM_TMPDIR', '/tmp')
+
+    def install(self, spec, prefix):
+        install_tree('.', prefix)