SecurityServices - allow integrator to run an action using the captured security context

Right now, an integrator must provide an instance of org.jboss.weld.security.spi.SecurityContext which is used to associate a captured security context with the current thread. However, the SPI should be more flexible. E.g. an integrator could provide a Consumer<Action> which would associate the security context automatically, when the action is performed (see for example WildFly Elytron SecutiryIdentity runAs methods).