Bug fixes

Improved API

The filter has to be run the last.

- Resolved a bug when extracting concepts from a file with a PowerTagging configuration with ConceptScheme restrictions.
- Fixed PHP warnings for PHP version 7.3+.
- Added a date selection filter for batch tagging.

Making sure the url is used from the form and that the module sends along the actual configuration when instantiating the plugin before submitting the changes.

Make sure the secret key is kept when the form is resubmitted. Also allow overrides of the oauth url using settings.php when using Dropsolid Platform authentication. Also make sure the form properties are respected.