Add possibility to set the code of the transaction

### Is your feature request related to a problem?

We cannot create a transaction with a content, to create a token for example

### Describe the solution you'd like

Set the content field to be updatable

### Additional context

Could create template for token creation

### Epic

_No response_

No files, tests, or entry points are named. Start by locating transaction creation and the content field, then trace how transaction codes are assigned; done means callers can set content and create a token transaction.

Written by the indexing model from the issue text.