Refactor the OCR app API

This refactor adds two new endpoints to view the OCR
content of versions and documents.

Signed-off-by: Roberto Rosario <Roberto.Rosario.Gonzalez@mayan-edms.com>

mayan/apps/ocr/serializers.py

@@ -2,10 +2,20 @@ from __future__ import unicode_literals
 
 from rest_framework import serializers
 
-from .models import DocumentPageOCRContent
+
+class DocumentOCRSerializer(serializers.Serializer):
+    text = serializers.CharField(
+        read_only=True, source='get_ocr_content'
+    )
 
 
-class DocumentPageOCRContentSerializer(serializers.ModelSerializer):
-    class Meta:
-        fields = ('content',)
-        model = DocumentPageOCRContent
+class DocumentPageOCRContentSerializer(serializers.Serializer):
+    text = serializers.CharField(
+        read_only=True, source='get_ocr_content'
+    )
+
+
+class DocumentVersionOCRSerializer(serializers.Serializer):
+    text = serializers.CharField(
+        read_only=True, source='get_ocr_content'
+    )