[Task]: Store Note's.aux field in the database

[igamigo]

Node's components affected by this task

• RPC
• Block producer
• Store
• Protobuf messages
• Testing

What should be done?

We are currently hardcoding aux fields of the note metadata internally. We should change the code to pass the value accordingly and storing it in the database.

How should it be done?

Add a column in the notes SQL table schema for the aux field, and store/retrieve it accordingly.

When is this task done?

When the SQL table includes the aux field and it is stored and retrieved accordingly.

Additional context

No response

[bobbinth]

Closed by #384.