Organize test folder (#894)

Adds library and framework subfolders for organizing tests in base test dir. Moves all library experiment tests into test/library subfolders.

Author: chriseclectic

test/quantum_volume/__init__.py renamed to test/framework/__init__.py

@@ -9,3 +9,4 @@
 # Any modifications or derivative works of this code must retain this
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
+"""Tests of experiments framework"""

test/test_composite.py renamed to test/framework/test_composite.py

@@ -9,3 +9,4 @@
 # Any modifications or derivative works of this code must retain this
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
+"""Tests for library experiments"""

test/test_framework.py renamed to test/framework/test_framework.py

@@ -0,0 +1,12 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2021.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+"""Tests for library calibration experiments"""