RoBo's gentoo overlay

Some useful ebuild for gentoo, which i miss in normal gentoo portage. Also, there are some updated packages, which are not (yet) in gentoo portage (and perhaps never will)

Changelog:

• 2018-10-24: hybrid-sources removed - use mptcp-sources
• 2023-05-01: mptcp-sources - not used anymore, all in the normal kernel :) old ebuild are here only for information
• 2023-05-02: add urbackup ebuild(s)
• 2023-11-01: removed outdated mptcp-sources