Make validation_resources a stable interface

Move the module to tempest.lib, add unit tests, release notes and
update imports.

Change-Id: I76b3b8e9a83bd83a6b5742b6d2ceb84642f653ad
diff --git a/doc/source/library.rst b/doc/source/library.rst
index a461a0f..074d642 100644
--- a/doc/source/library.rst
+++ b/doc/source/library.rst
@@ -69,3 +69,4 @@
    library/auth
    library/clients
    library/credential_providers
+   library/validation_resources
diff --git a/doc/source/library/validation_resources.rst b/doc/source/library/validation_resources.rst
new file mode 100644
index 0000000..9b36476
--- /dev/null
+++ b/doc/source/library/validation_resources.rst
@@ -0,0 +1,11 @@
+.. _validation_resources:
+
+Validation Resources
+====================
+
+-------------------------------
+The validation_resources module
+-------------------------------
+
+.. automodule:: tempest.lib.common.validation_resources
+   :members: