Make `path`, `fill_resource_method_name`, `submit_button`, and
`imageable_success_notice` dynamic based on the factory.
Also adjusted the user. The proposals no longer require the user to be an
administrator but do require them to be a level 2 user.
Note that we are adding the Style/CaseLikeIf rubocop rule.
Removed `imageable_path_arguments`, `has_many_images`, and `management` parameters
because they are not used by budgets.
Hardcoded `path`, `fill_resource_method_name`, `submit_button`, and
`imageable_success_notice`parameters for budgets. These remain fixed for now until dynamic
values are required in the next commits.
Using the `document` or `documents` classes meant styles defined for the
public list of documents conflict with these ones.
So now we're using HTML classes that match the name of the Ruby
component classes, as we usually do.
