LinkMojo creates symbolic links to artifacts

[mkarg]

This new mojo does the same as the copy mojo, but instead of really moving bytes around it simply creates symbolic links to the original storage location. When having to copy large amounts of data just for the sake of getting a particular on-disk structure in the end, this new mojo can spare huge amounts of time -- and plenty of disk space.

Warning: Windows requires users to have right to create symlinks, which by default only admins have in elevated mode. Hence TestLinkMojo and LinkMojo both will fail if not executed with sufficient access rights and / or elevated mode. This is not a bug but intended beavior of the Windows(R) operating system family. To effectively work with this mojo the user account should be a non-administrator, which got assigned the needed access rights by an administrator.

Note: This PR discovers a bug in plexus-utils, hence bug fix found in PR 13 is essentially needed to pass tests!

[mkarg]

As [PR 13] is merged meanwhile, I'd kindly like to ask for review now. :-)