jenkins: Install required jre in jenkins base profile

Without this change, applying the manifest on jenkins server the first time around just
fails the jenkins service as the jre is missing from the PATH.

Implementation wise, this moves the java install instruction into the jenkins base
profile as it's already a requirement for the agent.

Related to T3770

site-modules/profile/manifests/jenkins/agent.pp

 class profile::jenkins::agent {
   include profile::jenkins::base
-  include ::java
 
   $jenkins_agent_jar_url = lookup('jenkins::agent::jar_url')
   $jenkins_url = lookup('jenkins::backend::url')

site-modules/profile/manifests/jenkins/base.pp

 class profile::jenkins::base {
+  include ::java
+
   group {'jenkins':
     ensure => present,
     system => true,

[Phabricator Migration user]

Some references in the commit message have been migrated:

• T3770 is now swh/meta#3770 (closed)