smoketests

- less List instances required during spec-loading

- also makes the FacetHolderImpl thread-safe, which is required for

concurrent spec-loading

- profiling data shows, that basically most of the time is spent doing

reflective stuff like finding annotations including meta-annotations

Instead of writing or own reflection tools (with caching), we could

utilize those that Spring already provides.

- BackgroundService seems now obsolete, need to check whether it can be

removed

- new programming model allows to get hold of the Future that is

associated with the async action invocation

- type-safe async action invocation supports up to 4 arguments

(extensible)

- users are free to pick an ExecutorService for each individual async

execution, we default to the common ForkJoinPool

- handling of exceptions that occur during async invocation is not yet

well designed (API) or tested

- also removes the @Configuration annotation from 'IsisConfiguration'

which is just a bean

- instead annotate 'IsisConfigModule' with @Configuration

also fixes the sample apps and smoketests that got broken with one of

the previous config related commits today

- includes simplifications on how we might want to use lombok here

- also resurrecting smoketest 'SpringServiceProvisioningTest'

- such as @Incubating("does not work with surefire")

- fixed for Eclipse

- still needs fixing on IntelliJ: type inference issue with

fixtureScripts.runPersona(...)

- replaces the root of the DomainEvent class hierarchy

java.util.EventBase with org.apache.isis.applib.events.domain.EventObjectBase

- and use it with many of the FacetFactories

- also cleans up (de-duplicates) prefix constants

- in order to ease domain code migration (from 1.x to 2.x)

- also providing more precise specifications with associated java-doc