QBS.conf format

While the various tools to configure qbs from the command line or a GUI are fine, I have found myself editing the qbs.conf file manually a lot and that let me create toolchains more efficiently. 

However, the format used to store the settings is really a pain to work with.

I would suggest that either:

•   `qbs.conf` is replaced by a set of qbs files, one per profile so as to reduce the number of languages.
• `qbs.conf` use a less verbose, more maintainable format - And I think YAML would be a great choice/

I understand that this is a low-priority issue, take it more as a "if QBS is going to be rewritten without a Qt dep, we should consider the format we used to handle profiles"