INT-3749: Get rid of IECA logic

[artembilan]

JIRA: https://jira.spring.io/browse/INT-3749

Since IntegrationEvaluationContextAware isn't so "context-free" resource like BeanFactory
and ApplicationContext, but just a specific bean in the context, we can't follow with BeanPostProcessor logic - bad architecture by level of responsibility.
Therefore we should follow with standard Dependency Injection mechanism to retrieve evaluationContext for the particular component.

Since we can't rely on the @Autowired because SI can be used from the raw XML configuration,
we use utility method instead. The pattern to get the proper integrationEvaluationContext is:

 @Override
 protected void onInit() throws Exception {
        super.onInit();
        this.evaluationContext = ExpressionUtils.createStandardEvaluationContext(getBeanFactory());
 }

[garyrussell]

Won't this just take us back to the original problem? (early instantiation of everything due to getBeansOfType()) ?

[artembilan]

The "early access" issue has place in the BPP. When container calls afterPropertiesSet, all BPPs and bean are already there and ready to be access on normal manner.

[garyrussell]

ok; will review - we should remove the interface, and we'll need a migration guide entry

[artembilan]

Well, I made it backward compatible and deprecated as well.
Of course, we can remove this stuff altogether, but we can be smooth and even there is no need in migration guide note, because deprecation warn is thrown for the end-application.

[garyrussell]

Sorry - IDE problems - it showed no references 😦

[artembilan]

Right, it showed, because no one our class implements this interface any more, as well as all those our EXT projects, which are fixed by those my linked PRs.
I left it here just in case some other end-project uses our SpEL stuff for its purposes.

[garyrussell]

Rebased, merged.