Provide more information to the user when exporting model

[gblondet117]

Currently, OTFMI's functions export_fmu and export model, to export function from OpenTuRNS to .mo ou .fmu format does not provide any information about what was exported and where.

Adding a method to get information about model properties (example, the input format, the output format, etc.) could be valuable.

It could be a "pretty print" or a log file summarizing what's inside the model. Concerning the .mo format, at least, it could be an annotation inside the .mo model.

[jschueller]

todo: log the generated files