Feature: dataset attribute requiring a method entry

[mwallschlaeger]

Feature Description

To fulfill requirements of the the each column in the attribute table must have an optional method attached. This methods must be listed in a separate table in the database the methods must have the following properties:
**- method name

• method reference
• method descript
• ???**

To finish this issue:

• a new method model must be implemented
• an api endpoint including url, serializer and viewset must be implemented (view, edit, add, delete)
• an admin interface page must be created to edit, add, delete methods
• in advanced metadata editor methods must be selectable for each attribute of a dataset (except geocolumns)
• methods of an dataset attribute must be editable through the geonode dataset api endpoint

@krmeierzalf @CarstenHoffmann as you are working on the concept of a method database. Do you already have a full list of properties for the method database? Will this maybe involve more than one table?

note: #195

[mwallschlaeger]

use #197 as a reference for implementation

[specka]

Here we need input from the TF GeoNode, as its not clear, how we should ingest the method information from ORD to GeoNode.

[CarstenHoffmann]

@mwallschlaeger did you get response by Kristin to your request "Do you already have a full list of properties for the method database? Will this maybe involve more than one table?"
There is something available but should be provided by her.