create role widget and simplify all the different UI handlers for the SoftwarePlanVersion form
RoleForm is no longer used
remove unused utility
delete unused async handlers
simplify / cleanup accounting.utils
fix loading initial data of SoftwarePlanVersionForm and using correct POST data for each form in this view
add success message on updating SoftwarePlan
Merge pull request #2434 from dimagi/accounting-roles

Accounting roles widget for software plan version form