Proof of concept of the workflow instance context

Add support for workflow instance JSON context.
Add support for two step workflow transition.
Add support for dynamic form creation for transition execution.

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

mayan/apps/document_states/apps.py

@@ -40,6 +40,10 @@ from .links import (
     link_setup_workflow_state_edit, link_setup_workflow_transitions,
     link_setup_workflow_transition_create,
     link_setup_workflow_transition_delete, link_setup_workflow_transition_edit,
+    link_setup_workflow_transition_field_create,
+    link_setup_workflow_transition_field_delete,
+    link_setup_workflow_transition_field_edit,
+    link_setup_workflow_transition_field_list,
     link_tool_launch_all_workflows, link_workflow_instance_detail,
     link_workflow_instance_transition, link_workflow_runtime_proxy_document_list,
     link_workflow_runtime_proxy_list, link_workflow_preview,
@@ -86,6 +90,7 @@ class DocumentStatesApp(MayanAppConfig):
         WorkflowStateAction = self.get_model('WorkflowStateAction')
         WorkflowStateRuntimeProxy = self.get_model('WorkflowStateRuntimeProxy')
         WorkflowTransition = self.get_model('WorkflowTransition')
+        WorkflowTransitionField = self.get_model('WorkflowTransitionField')
         WorkflowTransitionTriggerEvent = self.get_model(
             'WorkflowTransitionTriggerEvent'
         )
@@ -257,6 +262,18 @@ class DocumentStatesApp(MayanAppConfig):
             )
         )
 
+        SourceColumn(
+            attribute='name', is_identifier=True, is_sortable=True,
+            source=WorkflowTransitionField
+        )
+        SourceColumn(
+            attribute='label', is_sortable=True, source=WorkflowTransitionField
+        )
+        SourceColumn(
+            attribute='required', is_sortable=True, source=WorkflowTransitionField,
+            widget=TwoStateWidget
+        )
+
         SourceColumn(
             source=WorkflowRuntimeProxy, label=_('Documents'),
             func=lambda context: context['object'].get_document_count(
@@ -305,10 +322,18 @@ class DocumentStatesApp(MayanAppConfig):
         menu_object.bind_links(
             links=(
                 link_setup_workflow_transition_edit,
-                link_workflow_transition_events, link_acl_list,
+                link_workflow_transition_events,
+                link_setup_workflow_transition_field_list,
+                link_acl_list,
                 link_setup_workflow_transition_delete
             ), sources=(WorkflowTransition,)
         )
+        menu_object.bind_links(
+            links=(
+                link_setup_workflow_transition_field_delete,
+                link_setup_workflow_transition_field_edit
+            ), sources=(WorkflowTransitionField,)
+        )
         menu_object.bind_links(
             links=(
                 link_workflow_instance_detail,
@@ -342,6 +367,12 @@ class DocumentStatesApp(MayanAppConfig):
                 'document_states:setup_workflow_list'
             )
         )
+        menu_secondary.bind_links(
+            links=(link_setup_workflow_transition_field_create,),
+            sources=(
+                WorkflowTransition,
+            )
+        )
         menu_secondary.bind_links(
             links=(link_workflow_runtime_proxy_list,),
             sources=(