Make PUT requests RFC compliant

Per the RFC specification for the HyperText Transfer Protocol our current implemented PUT request are not compliant with the specifications.

PUT request should receive the full object and update all the values, even if they are the same, missing data entity fields should be set to `None`.

This would require changes in cornflow-server, cornflow-client and cornflow-app

Review the PUT request handling across cornflow-server, cornflow-client, and cornflow-app, using the referenced HTTP RFC behavior as the specification. Trace how full objects and missing entity fields are processed. Done means PUT updates every field from the supplied object and assigns None to missing entity fields consistently across all three components.

Written by the indexing model from the issue text.