Revert "Removed ebuild of k3b, please use version in KDE repository if 9999 versions are wanted."

This reverts commit 34e7b28b17cf444798313615fcb4ad653dcfff74.
Managed to fix K3b but had to remove kde-base, versions were all older than those

in the gentoo repo and were no longer supported. If they were in use they should
automatically use the main tree instead.