New servicedelegationrule management module

[t-woerner]

There is a new servicedelegationrule management module placed in the plugins
folder:

plugins/modules/ipaservicedelegationrule.py

The servicedelegationrule module allows to ensure presence and absence of
servicedelegationrules and servicedelegationrule members.

Here is the documentation of the module:

README-servicedelegationrule.md

New example playbooks have been added:

playbooks/servicedelegationrule/servicedelegationrule-absent.yml
playbooks/servicedelegationrule/servicedelegationrule-principal-member-absent.yml
playbooks/servicedelegationrule/servicedelegationrule-principal-member-present.yml
playbooks/servicedelegationrule/servicedelegationrule-target-member-absent.yml
playbooks/servicedelegationrule/servicedelegationrule-target-member-present.yml
playbooks/servicedelegationrule/servicedelegationrule-present.yml

New tests for the module:

tests/servicedelegationrule/test_servicedelegationrule.yml
tests/servicedelegationrule/test_servicedelegationrule_client_context.yml
tests/servicedelegationrule/test_servicedelegationrule_hostprincipal.yml

[rjeffman]

In a first look, it LGTM.

If tests pass, I'll merge it as it is.

[varunmylaraiah]

LGTM