Add security checks to prevent directory traversal when decompressing…

[afeng2016-s]

This is a PR submission for #536

To verify that there is a directory traversal risk when unzipping the zip file, I test in FileUtilsTest.java.

1.Using the zipslip vulnerability, create a zip file.Save the created zip file in the D:/code/pf4j directory, if you do not have this path on your computer D drive, create it.

2. Next, call expandIfZip or loadPluginFromPath method to extract the zip file to the root directory of disk D of the computer.
   

3.To prevent path crossing problems caused by unsafe input, I recommend adding checks to the extract() method.

After adding the check, an exception is thrown when there is a malicious file name

Sorry, commits/c1b03c92c03cc42ef7d197d962acd785bbea60dd is wrong, commits/ed9392069fe14c6c30d9f876710e5ad40f7ea8c1 provide repair plan is correct.

[decebals]

Replaced by #538.
@afeng2016-s Thank you for your implication!