Option to exclude fields from DB

[rexa222]

It is a very common use case that a field is needed in a document class that handles stuff in the code and it must not be included in the DB… The infrastructure for excluding fields is obviously available as there is a revision_id field that exists in model_fields but does not appear in DB… but the option is not available for other fields which is really necessary. (For example, when exclude=True in Field the fields can get excluded from DB… or a new extra field to avoid confusion with the exclude arg)

[staticxterm]

Hi @rexa222 , PR #1154 should add proper support for the Pydantic "exclude" option.