Add setup roles for passlib and pexpect for use with pause and vars_prompt tests (#43613)

* Add passlib to RHEL test instance

This looks like the only tests instance that is missing this libary. It is needed for vars_prompt tests.

* Create setup roles for pexect and passlib

Switch to using aliases rather than installing directly in the test scripts

test/integration/targets/pause/aliases

@@ -1 +1,2 @@
+setup/always/setup_pexpect
 shippable/posix/group3

test/integration/targets/pause/runme.sh

@@ -25,5 +25,4 @@ ansible-playbook pause-3.yml -i ../../inventory > /dev/null \
 ansible-playbook test-pause.yml -i ../../inventory "$@"
 
 # Interactively test pause
-pip install pexpect
 python test-pause.py -i ../../inventory "$@"

test/integration/targets/setup_passlib/tasks/main.yml

@@ -0,0 +1,4 @@
+- name: Install passlib
+  pip:
+    name: passlib
+    state: present

test/integration/targets/setup_pexpect/tasks/main.yml

@@ -0,0 +1,4 @@
+- name: Install pexpect
+  pip:
+    name: pexpect
+    state: present

test/integration/targets/vars_prompt/aliases

@@ -1 +1,3 @@
+setup/always/setup_passlib
+setup/always/setup_pexpect
 shippable/posix/group2

test/integration/targets/vars_prompt/runme.sh

@@ -2,14 +2,5 @@
 
 set -eux
 
-# Install passlib on RHEL and FreeBSD
-dist=$(python -c 'import platform; print(platform.dist()[0])')
-system=$(python -c 'import platform; print(platform.system())')
-
-if [[ "$dist" == "redhat" || "$system" == "FreeBSD" ]]; then
-    pip install passlib
-fi
-
 # Interactively test vars_prompt
-pip install pexpect
 python test-vars_prompt.py -i ../../inventory "$@"