Layers admin interface raise error

[mattiagiupponi]

Expected Behavior

After accessing the admin page, as an admin i'm able to modify the dataset metadata

Actual Behavior

The admin interface raises an error so is not possible to update any metadata related to the dataset.
Analyzing the error, looks like that the thasaurus autocomplete endpoint is not available (maybe has been renamed during the metadata manager upgrade)

It should be enough to update the DatasetAdminForm by replacing the URL thesaurus_autocomplete with the new one metadata_autocomplete_tkeywords

Steps to Reproduce the Problem

1. Open the admin interface
2. Try to modify a dataset

Specifications

• GeoNode version: master
• Installation type (vanilla, geonode-project): any
• Installation method (manual, docker): any
• Platform:
• Additional details: