DELTASPIKE-382 add ConfigFilter mechanism

This allows to filter DeltaSpike configuration values,
e.g. for applying decryption of secure configuration values
on the fly.
DELTASPIKE-386 use correct ClassLoader for loading the ResourceBundle

txs to Richard DiCroce for the catch!
fix old TODO and use field injection of Extension.
remove useless TODOs
remove unused private field
fix documentation for custom ProjectStages
removed obsolete TODO for Weld

This scenario must not happen. The ClassLoader used to load
the Extension is also the one used at shutdown. Even in EAR
scenarios with a hierarchic setup we will hopefully get the
correct TCCL. The mem will get freed up lastest after the EAR
gets undeployed anyway. Sparse re-deployments of portions of
an EAR are not guaranteed to work by the EE spec neither.
review old TODOs and remove them if not valid anymore.
DELTASPIKE-387 Created new name for the module.
DELTASPIKE-387 Renamed package.
DELTASPIKE-387 Changed test package name.
Minor javadoc cleanup in servlet module