Upgrade to upstream version 2.8.0

Import the upstream version 2.8.0, updating corresponding copyrights, and adapt the package to properly build with the new source. Patches to known bugs already integrated into the upstream master branch have been backported to improve the quality of the shipped binary.

This MR does not intend to package the new software introduced in the 2.8.0 release: procServUtils, which is a Python package providing scripts to manage procServ instances under systemd. This can be done in a follow up MR, so review process becomes easier.