WELD-1791 Revisit configuration

- introduce WeldConfiguration per-deployment service
- supported configuration keys can be found in ConfigurationKey enum
WELD-1791 Make findbugs happy
replace expression to contains
WELD-1802 moved clearing of bean store and clean up to finally clause
WELD-1802 destroying conversation if an exception occurs when attaching bean store
WELD-1774 Fix conversation context activation/association

- do not throw an exception when the conversation context is already
active (just log a warning that it's most likely a ThreadLocal leak)
- always associate the conversation context with the current HTTP
request
Minor
Revert "WELD-1802 destroying conversation if an exception occurs when attaching bean store"

This reverts commit 311dd7916304b6275a4790bb77b8cccd6694c068.

The destruction of the conversation is not necessary. If an HTTP session times out all the conversations are destroyed automatically (in a seperate thread). Moreover the fix for WELD-1774 prevents from using leaked associated HTTP requests.
WELD-1802 Adding test to simulate the leaking scenario
WELD-1787 Introduce ResolvedObservers
WELD-1787 Cache ResolvedObservers and EventMetadata within EventImpl
WELD-1787 Make code more reusable
WELD-1787 Make it possible for a TypeSafeResolver to return a different type after finalizing
WELD-1787 Get rid of EventPacket
WELD-1787 Cache whether event metadata is required by any of the observers
WELD-1787 Various improvements to resolvables
WELD-1787 Various improvements to QualifierInstance
WELD-1787 Make MethodInjectionPoint optimization more general
WELD-1787 Introduce ObserverMethodInvocationStrategy
WELD-1787 Apply MethodInjectionPoint optimization to all callables