Introduce new helper: call_and_ignore_notfound_exc()

This new function calls a function passed as parameter and ignore
the NotFound exception if it raised.

This removes some code duplication.

Also a new `test_utils` module is introduced to tempest.lib and the
`find_test_caller` function is moved into that new module. Backward
compatibility and deprecation path are ensured and documented.

Note for the future: having a module called "misc" is not optimal because
the name is not super descriptive. (it's a detail though, but worth
mentioning imo).

Change-Id: I5a4523c20c19957bfccf2aa95157baf106b3d364
diff --git a/releasenotes/notes/new-test-utils-module-adf34468c4d52719.yaml b/releasenotes/notes/new-test-utils-module-adf34468c4d52719.yaml
new file mode 100644
index 0000000..55df2b3
--- /dev/null
+++ b/releasenotes/notes/new-test-utils-module-adf34468c4d52719.yaml
@@ -0,0 +1,11 @@
+---
+features:
+  - A new `test_utils` module has been added to tempest.lib.common.utils. It
+    should hold any common utility functions that help writing Tempest tests.
+  - A new utility function called `call_and_ignore_notfound_exc` has been
+    added to the `test_utils` module. That function call another function
+    passed as parameter and ignore the NotFound exception if it raised.
+deprecations:
+  - tempest.lib.common.utils.misc.find_test_caller has been moved into the
+    tempest.lib.common.utils.test_utils module. Calling the find_test_caller
+    function with its old location is deprecated.