Fix remote_tmp when become with non admin user (#42396)

* Fix tmpdir on non root become

 - also avoid exception if tmpdir and remote_tmp are None
 - give 'None' on deescalation so tempfile will fallback to it's default behaviour
   and use system dirs
 - fix issue with bad tempdir (not existing/not createable/not writeable)
   i.e nobody and ~/.ansible/tmp
 - added tests for blockfile case

* Revert "Temporarily revert c119d54"

This reverts commit 5c614a59a6.

* changes based on PR feedback and changelog fragment

* changes based on the review

* Fix tmpdir when makedirs failed so we just use the system tmp

* Let missing remote_tmp fail

If remote_tmp is missing then there's something more basic wrong in the
communication from the controller to the module-side.  It's better to
be alerted in this case than to silently ignore it.

jborean and I have independently checked what happens if the user sets
ansible_remote_tmp to empty string and !!null and both cases work fine.
(null is turned into a default value controller-side.  empty string
triggers the warning because it is probably not a directory that the
become user is able to use).

lib/ansible/modules/packaging/os/yum.py

@@ -340,7 +340,7 @@ def ensure_yum_utils(module):
 def fetch_rpm_from_url(spec, module=None):
     # download package so that we can query it
     package_name, _ = os.path.splitext(str(spec.rsplit('/', 1)[1]))
-    package_file = tempfile.NamedTemporaryFile(prefix=package_name, suffix='.rpm', delete=False)
+    package_file = tempfile.NamedTemporaryFile(dir=module.tmpdir, prefix=package_name, suffix='.rpm', delete=False)
     module.add_cleanup_file(package_file.name)
     try:
         rsp, info = fetch_url(module, spec)