Validate multiple datasets at once

• As a user,
• I want to be able to input multiple files (upload or URL),
• in order to easily validate at once as many datasets as I need.

Acceptation criteria

• Adapt (if needed) Good Tables API for multiple file input (or call Good Tables API multiple times)
• Adapt Good Tables form module for multiple file input
• Adapt Qualidata validation report for multiple files (using multiple Good Tables report modules)