[KARAF-3130]add admin:change-ssh-host command
(cherry picked from commit 119e9fecb20633ea98664ccda532bb9cb2f286a1)

Conflicts:
	admin/management/src/main/java/org/apache/karaf/admin/management/internal/AdminServiceMBeanImpl.java
	instance/command/src/main/resources/OSGI-INF/blueprint/instance-command.xml
	instance/core/src/main/java/org/apache/karaf/instance/core/Instance.java
	instance/core/src/main/java/org/apache/karaf/instance/core/InstancesMBean.java
	instance/core/src/main/java/org/apache/karaf/instance/core/internal/InstanceImpl.java