What would you want to do with a database dump in Plone?.
Very few people will need support for this. Thus, I doubt that this use case will be supported by tools/add-ons.
If your Plone runs on the same host as the database, there is a chance: in a view (specially protected) you can use database command line tools (called via
os.system or functions from the
subprocess module) to produce a dump. You then use Plone commands to put the file into Plone.
Note, however, that databases usually contain sensible data. Therefore, special security applies for the creation of dumps. You must take action to overcome those security measures (which are less related to Plone but to the database and your system). If your database contains sensible data, you must take steps to protect access to a database dump loaded into Plone.