Allowing use of non-static permissions

This patch add possibility turn on non-static permissions by new property ``` jboss.modules.policy-refreshable ```

If it is ``` true ```, permissions from Policy will be used, like with ``` jboss.modules.policy-permissions ```, but change of used policy without restart of the server will be possible.
(It will be possible as in case of ``` URLClassLoader ```, which use non-static permisions by default, by using of ``` Policy.getPolicy.refresh() ```)

Because if it is used, speed of the server decreases, it is optional by mentioned property.
For use of it have to be added into start script of WildFly:
```
JAVA_OPTS="$JAVA_OPTS -Djboss.modules.policy-refreshable=true"
```
(I am currently working on thesis, whichs output is extension allowing mentioned switching of security policy at runtime: https://github.com/honza889/jsm-policy-subsystem)