New configuration managment with "class Konfig" in version 1.6.1

[buhtz]

While preparing the 1.5.3 release (PR #1922) I realized that the helper script "create-manpage-backintime-config.py" is broken. I can tell by the diff that some config entries are lost in the man page. The code is hard to read and I don't want to waste time on it anymore.

We do have a pending PR (#1850) offering a new config class including auto generating the man page.

The plan is to migrate to that new class in version 1.6.1.