useradd: Fix issues with useradd dependencies

If recipe A requires the useradd actions of recipe B we need to
ensure that recipe B is part of the recipe A dependancy chain. In
order to do that, we introduce USERADD_DEPENDS. This makes sure
that the do_populate_sysroot_setscene of recipe B exists for
recipe A in case of a missing TMPDIR. This requires changes made in
runqueue.py by RP.

This commit along with the runqueue fixes effects:
Bug 13419 - recipes that add users to groups cannot rely on other recipes creating those groups (when population from sstate happens)
Bug 13904 - do_prepare_recipe_sysroot: postinst-useradd-* does not run in order of dependency and sometimes fails
Bug 13279 - Make sure users/groups exist for package_write_* tasks
Bug 15084 - For some reason using of same user in two recipes does not work properly

I've included the start of self-testing for useradd by adding tests for
13419 (which ends up testing 13904, 13279, 15084 by virtue of them all
      having the same root cause)

(From OE-Core rev: b47f2352376bd16b7e7087b4dab143403e67e094)

Signed-off-by: Eilís 'pidge' Ní Fhlannagáin <pidge@baylibre.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/selftest/cases/usergrouptests.py

@@ -0,0 +1,17 @@
+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: MIT
+#
+
+from oeqa.selftest.case import OESelftestTestCase
+from oeqa.utils.commands import bitbake
+
+class UserGroupTests(OESelftestTestCase):
+    def test_group_from_dep_package(self):
+        self.logger.info("Building creategroup2")
+        bitbake(' creategroup2 creategroup1')
+        bitbake(' creategroup2 creategroup1 -c clean')
+        self.logger.info("Packaging creategroup2")
+        self.assertTrue(bitbake(' creategroup2 -c package'))
+