The current file submission is hard coded to a maximum of 20 files
possible. While the user can choose a number less than 20, the maximum
is still set in code. This converts the hard coded 20 to a site setting
defaulting to 20.
Non-standard means php.ini was set to something not in the default list (like 7MB),
then the config was saved to that specific value, and now the value in php.ini has been changed
again so 7MB does not appear in the list.
Also move the 'default' setting for each plugin into it's own settings file
so that it is handled properly on new installs.
(ensure the plugin is available at setting time)
Also make the file submission plugin on by default