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.
