config nestedness, yaml and toml

I switched to toml, because I had an issue with the nestedness of the config and because I wanted to get rid of C-extensions in pyaptly. I did not find an acceptable pure python yaml parser.

While the converter from yaml to toml did an ok job for the configs we use in our tests. It made a complete mess on the existing productions configs. Currently I think, there is a nice config that is correct toml, but the converter is just messing it up.

What I am going to do:

• Try to fix the converter

Questions:

• Is manual cleanup acceptable if we can't fix the converter?
• Do we really need to get rid of C-extensions?
• Should we just support toml and yaml?
• Forget toml completely?
• Should the nestedness be fixed in the data-structure?