Add a curation log when an author is manually added or removed from a dataset

[molcretb]

User Story

As a curator
I want to keep audit log of assignment and unassigment of authors from dataset
So that I can keep a trace of changes of authorship of datasets

Acceptance tests

Given there is a non-published dataset I wish to amend the authorship of
When I add an author to that dataset
Then there should be a new curation log entry with the new author's details

Given there is a non-published dataset I wish to amend the authorship of
When I update an author of that dataset
Then there should be a new curation log entry with the author's new details

Given there is a non-published dataset I wish to amend the authorship of
When I remove an author of that dataset
Then there should be a new curation log entry with the removed author's details

Given there is a published dataset I wish to amend the authorship of
When I add an author to that dataset
Then there should be a new dataset history entry with the new author's details

Given there is a published dataset I wish to amend the authorship of
When I update an author of that dataset
Then there should be a new dataset history entry with the author's new details

Given there is a published dataset I wish to amend the authorship of
When I remove an author of that dataset
Then there should be a new dataset history entry with the removed author's details

Feature request

For curation purposes, when a new author is added to a dataset through the admin tools, it must get added to the related dataset curation log.

As a curator
When I add an author to an existing dataset using the admin tool page 'Dataset:Authors'
Then a log is automatically added to the dataset logs with the details of the new author

As a curator
When I remove an author from an existing dataset using the admin tool page 'Dataset:Authors'
Then a log is automatically added to the dataset logs with the details of the removed author