Feature: [docgen] generate documents in an async queue

The documents are now generated in a queue, using symfony messenger. This queue should be configured:

```yaml
# app/config/messenger.yaml
framework:
    messenger:
        # reset services after consuming messages
        # reset_on_message: true

        failure_transport: failed

        transports:
            # https://symfony.com/doc/current/messenger.html#transport-configuration
            async: '%env(MESSENGER_TRANSPORT_DSN)%'
            priority:
                dsn: '%env(MESSENGER_TRANSPORT_DSN)%'
            failed: 'doctrine://default?queue_name=failed'

        routing:
            # ... other messages
            'Chill\DocGeneratorBundle\Service\Messenger\RequestGenerationMessage': priority
```

`StoredObject`s now have additionnal properties:

* status (pending, failure, ready (by default) ), which explain if the document is generated;
* a generationTrialCounter, which is incremented on each generation trial, which prevent each generation more than 5 times;

The generator computation is moved from the `DocGenTemplateController` to a `Generator` (implementing `GeneratorInterface`. 

There are new methods to `Context` which allow to normalize/denormalize context data to/from a messenger's `Message`.

src/Bundle/ChillPersonBundle/Resources/public/vuejs/AccompanyingCourseWorkEdit/components/FormEvaluation.vue

@@ -116,6 +116,7 @@
                          :filename="d.title"
                          :can-edit="true"
                          :execute-before-leave="submitBeforeLeaveToEditor"
+                         @on-stored-object-status-change="onStatusDocumentChanged"
                      ></document-action-buttons-group>
                    </li>
                    <li v-if="d.workflows.length === 0">
@@ -338,6 +339,10 @@ export default {
             this.$store.commit('removeDocument', {key: this.evaluation.key, document: document});
          }
       },
+      onStatusDocumentChanged(newStatus) {
+        console.log('onStatusDocumentChanged', newStatus);
+        this.$store.commit('statusDocumentChanged', {key: this.evaluation.key, newStatus: newStatus});
+      },
       goToGenerateWorkflowEvaluationDocument({event, link, workflowName, payload}) {
          const callback = (data) => {
             let evaluation = data.accompanyingPeriodWorkEvaluations.find(e => e.key === this.evaluation.key);

src/Bundle/ChillPersonBundle/Resources/public/vuejs/AccompanyingCourseWorkEdit/store.js

@@ -360,7 +360,22 @@ const store = createStore({
         state.evaluationsPicked.find(e => e.key === payload.evaluationKey)
           .documents.find(d => d.id === payload.id).title = payload.title;
       }
-    }
+    },
+    statusDocumentChanged(state, {newStatus, key}) {
+      const e = state.evaluationsPicked.find(e => e.key === key);
+      if (typeof e === 'undefined') {
+        console.error('evaluation not found for given key', {key});
+      }
+
+      const doc = e.documents.find(d => d.storedObject?.id === newStatus.id);
+      if (typeof doc === 'undefined') {
+        console.error('document not found', {newStatus});
+      }
+
+      doc.storedObject.status = newStatus.status;
+      doc.storedObject.type = newStatus.type;
+      doc.storedObject.filename = newStatus.filename;
+    },
   },
   actions: {
     updateThirdParty({ commit }, payload) {