Remove policytool from doc

JDK-8148371 removes policytool from JDK. All referecnes of it should be removed from documents.

For example, https://docs.oracle.com/javase/9/tools/policytool.htm#JSWOR698 and https://docs.oracle.com/javase/tutorial/security/tour1/wstep1.html should be removed. The link in
https://docs.oracle.com/javase/tutorial/security/tour1/step2.html should be removed.

These are just examples, and there might be more.

Please feel free to create more bugs if tooldoc and tutorial must be covered in different bugs.