adding save of build times on install (#24350)

Here we are adding an install_times.json into the spack install metadata folder.
We record a total, global time, along with the times for each phase. The type
of phase or install start / end is included (e.g., build or fail)

Signed-off-by: vsoch <vsoch@users.noreply.github.com>

Co-authored-by: vsoch <vsoch@users.noreply.github.com>

var/spack/repos/builtin.mock/packages/dev-build-test-install-phases/package.py

@@ -0,0 +1,30 @@
+# Copyright 2013-2021 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 time import sleep
+
+
+class DevBuildTestInstallPhases(Package):
+    homepage = "example.com"
+    url = "fake.com"
+
+    version('0.0.0', sha256='0123456789abcdefgh')
+
+    phases = ['one', 'two', 'three', 'install']
+
+    def one(self, spec, prefix):
+        sleep(1)
+        print("One locomoco")
+
+    def two(self, spec, prefix):
+        sleep(2)
+        print("Two locomoco")
+
+    def three(self, spec, prefix):
+        sleep(3)
+        print("Three locomoco")
+
+    def install(self, spec, prefix):
+        print("install")