I can probably scavange from some old local user mgmt code I have, mostly js and php. Still not sure about LDAP user mgmt, the client has an ldp server so it's required and the software needs local user management too for resale. Once mgmt and auth is in place... then I'll need to implement page permissions, file/asset permissions, DB permissions, credential mgmt for numerous external REST & DB systems, and I'm sure that's probably only 10% of it.
Doing it all from scratch (again,lol) in any language would take 2-4 weeks just for complete auth, login/out, users, groups, roles, assigning users to groups and etc.