[FEAT] Manage BPMN input source parsing warnings/errors

[tbouffard]

Is your feature request related to a problem? Please describe. The lib should provide feedback and/or callbacks for any parsing errors/warnings that occurs on BPMN source input load.

Describe the solution you'd like In the 1st implementation (#22), we skip this part as we only managed the happy path. As a consequence, some TODO remain in the code. As for #21, we must manage all runtime parsing errors/warnings to provide feedback to the end user or allow the developer who integrates our lib to detect them.

Describe alternatives you've considered N/A

Additional context N/A

[tbouffard]

This may be managed by #54

[tbouffard]

In v0.19.0, we introduced an internal mechanism to collect the parsing warnings. See #1479. The warnings are currently only logged in the console, but the infrastructure is here to be able to return them at the end of the load processing.