Support image uploads in the "notes" markdown fields (#4615)

* Support image uploads in the "notes" markdown fields

- Implemented using the existing EasyMDE library
- Copy / paste support
- Drag / drop support

* Remove debug message

* Updated API version

* Better UX when saving notes

* Pin PIP version (for testing)

* Bug fixes

- Fix typo
- Use correct serializer type

* Add unit testing

* Update role permissions

* Typo fix

* Update migration file

* Adds a notes mixin class to be used for refactoring

* Refactor existing models with notes to use the new mixin

* Add helper function for finding all model types with a certain mixin

* Refactor barcode plugin to use new method

* Typo fix

* Add daily task to delete old / unused notes

* Bug fix for barcode refactoring

* Add unit testing for function

InvenTree/company/migrations/0056_alter_company_notes.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.2.18 on 2023-04-19 00:37
+
+import InvenTree.fields
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('company', '0055_auto_20230317_0816'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='company',
+            name='notes',
+            field=InvenTree.fields.InvenTreeNotesField(blank=True, help_text='Markdown notes (optional)', max_length=50000, null=True, verbose_name='Notes'),
+        ),
+    ]