Use valid XML for config files

[rubenhorn]

Issue

Currently, the MaMiCo configuration XML files have multiple root nodes, but according to the XML standard there should be only one, so other parsers may not be able to read them.

Solution

Updating the configuration parser to deal with a single root note (similar to ls1) containing the current configuration structure (similar to ls1):

<?xml version="1.0" encoding="UTF-8"?>
<scenario-configuration>
   <!-- contents of the old configuration file format -->
</scenario-configuration>

All example configuration files should be updated accordingly. The parser should still be able to handle the legacy format for compatibility with old configuration files.

Steps

• [x] Refactor the XML parsing
• [x] Update (or write) unit tests for the new AND old configuration formats
• [x] Update the example configuration files