Up until this commit, HTML fields created from the UI or via data
modules or via Studio where alway sanitized, without any possibility of
control by the developper or db admin.
This commit makes it possible to override these attributes for
data-defined fields (python-defined fields cannot be overriden).
This makes it possible to create fields that can e.g. be used as 'block
targets' in the website editor for data modules.
closesodoo/odoo#130544
Related: odoo/enterprise#47116
Related: odoo/upgrade#5290
Signed-off-by: Lucas Perais (lpe) <lpe@odoo.com>