Added initial support for impersonation added

Conflicts:

	portlet/exoadmin/src/main/java/org/exoplatform/organization/webui/component/UIListUsers.java
	portlet/exoadmin/src/main/resources/locale/portlet/exoadmin/OrganizationPortlet_en.properties
	portlet/exoadmin/src/main/webapp/groovy/admintoolbar/webui/component/UIStarToolBarPortlet.gtmpl

Conflicts:

	portlet/exoadmin/src/main/java/org/exoplatform/organization/webui/component/UIListUsers.java
	web/portal/src/main/webapp/WEB-INF/web.xml
GTNPORTAL-3089 - added css files and impersonation icon
Added backup/restore of attributes to be cross-context aware. Removed SessionInvalidatorInterceptor from PC stack. Allow impersonation for disabled users.

Conflicts:

	pom.xml
	webui/portal/src/main/java/org/exoplatform/portal/application/PortalLogoutLifecycle.java
GTNPORTAL-2662 Impersonation in GateIn
GTNPORTAL-3245: Add comfriming when user remove permissions on edit page & site