Fixed dangling javadoc comment warning for license header

[Hakky54]

I was scrolling through the source code and I noticed a warning that the license header is marked as dangling javadoc comment I did some research and found out that the better way is to have a license header in the following format:

/*
 *
 */

Instead of:

/**
 *
 */

I don't think the existing header is incorrect formatted but my idea gave warnings and this was a way to resolve it. Not quite sure if you guys want this change. Because I change the format the copyright date needed to be updated to 2021 because of the maven license plugin scan. Looking to hear from you soon.

[velo]

The PR ia massive and risk introducing unwanted changes.

If you want, just make the pom.xml change, and I will checkout the branch, apply license:format and push