Manage plugins versions centrally.
Refactor WSSecurity. Use URLs as methid patams when possible.
Reorder methods.
Load properties at the constructor, when possible.

SecurityPasswordCallback still loads the properties itself.
This is because we don't want the password to be in memory,
but to be read when required.
Load SecurityPasswordCallback at WSSecurity constructor.
Separate WSSecurity loading and functionallity in different classes.

WSSecurityLoader is responsible for creating configured WSSecurity instances.
It loads required Properties files and instantiates WSSecurity with required values.

WSSecurity is no longer responsible for reading Properties from URLs.
SecurityPasswordCallback is still responsible for loading a Properties file from given URL, in order to read the password.
Export WSSecurityLoader as an OSGi service with IWSSecurityFactory interface.
Merge branch 'feature/refactor-wssec' into develop