Detect importer for XML files

[kaklakariada]

Is your feature request related to a problem? Please describe.
Currently OFT decides on the file name which importer to use. This means that only one importer (i.e. SpecobjectImporterFactory') can import files with the .xmlsuffix. Also a project might contain XML files in a different format (e.g. Maven'spom.xmlfiles) thatSpecobjectImporterFactory' does not support and will log a warning about.

Describe the solution you'd like
We need an XML detector that determines the type of XML files based on the content and delegates to the relevant XML importer.

Describe alternatives you've considered
Using different file suffixes for all XML based formats might not be sufficient in all projects.

Additional context