Depend on teklia-document-processing PyPi package

Refs https://redmine.teklia.com/issues/6260

Need: !82 (merged)

docs/dev.md

@@ -2,10 +2,17 @@
 
 ## Base setup
 
+This package is based on a GitLab package registry containing all the document processing source code.
+You need [a personal access token](https://docs.gitlab.com/ee/user/profile/personal_access_tokens.html) and access to the [teklia-document-processing repository](https://gitlab.teklia.com/tools/document-processing) in order to install this module. You will need to add the below to your `~/.netrc` file:
+
+```shell
+machine gitlab.teklia.com
+login __token__
+password <YOUR_PERSONAL_TOKEN>
+```
+
 - Use a virtualenv (e.g. with virtualenvwrapper `mkvirtualenv -a . atr-data-gen`)
-- Install atr-data-generator as a package from a local clone:
-    1. The `teklia-document-processing` library is setup via git submodule. Please run `git submodule update --init`.
-    1. Then install both packages via `pip install ./document-processing -e .`
+- Install `atr-data-generator` as a package (e.g. with pip `pip install --index-url https://gitlab.teklia.com/api/v4/projects/149/packages/pypi/simple -e .`)
 
 ## Unit tests