Cloudscale server password (#53701)

* cloudscale_server: remove required parameter check

The valid parameter combinations are already checked by the API. There
is no need to check a subset of this in the Ansible module as well. This
makes it more likely that future changes in the API won't require
changes in the Ansible module.

* cloudscale_server: add password parameter

Recent revisions of the cloudscale.ch API allow setting a password for a
server. Add this option to the cloudscale_server module.

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

@@ -0,0 +1,6 @@
+---
+# Password to use for test server
+# This has to be set as a fact, otherwise a new password will be generated
+# on every variable access.
+- set_fact:
+    cloudscale_test_password: "{{ lookup('password', '/dev/null length=15 chars=ascii_letters') }}"