feat/publish upload updates

[aspedrosa]

Since this application can be used as a third-party application in another main application, some information that is uploaded to a data source on this application might also be present on the main application, so an update feature is important and useful.

Description

• we use requests python library to sent requests
• these requests are groups in groups allowing to send several requests to the same server after an upload is done.
  • Each group can be deactivated
• to define the URL, method, and other request parameters the application admin must provide a Jinja2 template, where he has access to the data that was uploaded, the data source model object of the data source to which the data is being uploaded to and the response objects returned by the previous requests of the same RequestsGroup.
  • I choose to use Jinja2 instead of Django's template buildtin system since the latter is more restricted and more HTML-oriented.
  • Some examples and more documentation are present on the new model's help_text fields

How Has This Been Tested?

Django tests