Use the idempotent id and tooling from tempest-lib

The idempotent id decorator and the check-uuid script were migrated to
tempest-lib as part of tempest-lib 0.10.0. However, tempest was never
updated to use the library version of idempotent id or check-uuid.
This commit updates tempest to remove it's local copies of the
idempotent_id decorator and the check-uuid tool and use them from
tempest-lib instead.

Also, instead of updating the import of every single test module in
tempest an alias is just added to tempest.test to let all the old
imports work seamlessly. Updating the imports and removing the alias
may or may not be worth it in the future, but that will be a follow
on patch or discussion.

Change-Id: Iae3f491ada8f7b55c1fd817e033d968c2102d11e
diff --git a/tox.ini b/tox.ini
index ecd4f24..41eece1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -114,11 +114,11 @@
 [testenv:pep8]
 commands =
    flake8 {posargs}
-   python tools/check_uuid.py
+   check-uuid
 
 [testenv:uuidgen]
 commands =
-   python tools/check_uuid.py --fix
+   check-uuid --fix
 
 [hacking]
 local-check-factory = tempest.hacking.checks.factory