AMBARI-24907. Updated service metainfo to declare LDAP integration support

[smolnar82]

What changes were proposed in this pull request?

Update service metainfo to declare LDAP integration support. The following tag may be optionally set in a service's metainfo.xml file:

<ldap>
 <supported>true</supported>
 <ldapEnabledTest>
    {
      "equals": [
        "ranger-admin-site/ranger.authentication.method",
        "LDAP"
      ]
    }
 <ldapEnabledTest>
</ldap>

How was this patch tested?

Executing JUnit tests in ambari-server:

[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 25:22 min
[INFO] Finished at: 2018-11-16T07:37:57+01:00
[INFO] Final Memory: 163M/917M
[INFO] ------------------------------------------------------------------------

In addition to unit testing the following E2E tests have been done locally:

1. had a cluster with Ranger, Zookeeper and AMS installed
2. modified Ranger's metainfo.xml and added the above ldap XML elements
3. built the new JAR, replaced the old one with the new and restarted the server
4. Checked the service response for Ranger using Ambari's API
   4.1. authentication method was set to UNIX (the default one):

4.2. updated Ranger's authentication method to LDAP:

5. Checked the service response for Ranger using Ambari's API (there was no <ldap> setting here):

[asfgit]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/Ambari-Github-PullRequest-Builder/4562/
Test FAILed.
Test FAILured.

[benyoka]

LGTM wtr the checkstyle fix.

[asfgit]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/Ambari-Github-PullRequest-Builder/4563/
Test PASSed.

[rlevas]

Maybe for code reuse, make compileKerberosEnabledPredicate generic?

  private Predicate compilePredicate(String json) {
    if (StringUtils.isNotBlank(json)) {
      return PredicateUtils.fromJSON(json);
    }
    return null;
  }

[rlevas]

oops.. already merged... :|