remove support for the Security Manager

[Ladicek]

The Security Manager was deprecated for removal in Java 17 (JEP 411) and shall be permanently disabled in Java 24 (JEP 486). Therefore, we should remove the few bits that enable running SmallRye Fault Tolerance with Security Manager enabled; this mostly concern the two SecurityActions classes in this project, plus a small number of other classes that refer to java.security.*.

I'm tentatively assigning this to the 7.0.0 milestone, but could probably be persuaded to do this sooner.

[rhusar]

Please don't execute on this yet until we have a clear alignment with WildFly. Hopefully this won't be a problem for 7.x but lets make sure jumping the gun won't make us have to support 2 branches.