#18 File upload in certain folders

* refactors documents and file upload to be distributed into different subfolders, depending on the type of document (InterventionDocument, RevocationDocument, ...)
* refactors Document model into AbstractDocument
* subclasses RevocationDocument, InterventionDocument, COmpensationDocument, EmaDocument and EcoAccountDocument from AbstractDocument to provide proper functionality for each
* adds new specialized routes for each new document type (opening, removing)
* drops generic get and remove routes for documents

ema/models.py

@@ -2,7 +2,8 @@ from django.contrib.auth.models import User
 from django.db import models
 
 from compensation.models import AbstractCompensation
-from konova.settings import DEFAULT_SRID_RLP, LANIS_LINK_TEMPLATE
+from konova.models import AbstractDocument, generate_document_file_upload_path
+from konova.settings import DEFAULT_SRID_RLP, LANIS_LINK_TEMPLATE, EMA_DOC_PATH
 from user.models import UserActionLogEntry
 
 
@@ -83,4 +84,18 @@ class Ema(AbstractCompensation):
 
         # ToDo: Add check methods!
 
-        return ret_msgs
+        return ret_msgs
+
+
+class EmaDocument(AbstractDocument):
+    """
+    Specializes document upload for ema with certain path
+    """
+    instance = models.ForeignKey(
+        Ema,
+        on_delete=models.CASCADE,
+        related_name="documents",
+    )
+    file = models.FileField(
+        upload_to=generate_document_file_upload_path
+    )