Scriptable property mappings for LDAP outpost

**Is your feature request related to a problem? Please describe.**
I think it would be a really useful feature to have "scriptable" LDAP properties, much like the scope mappings in OAuth2/OIDC land, so someone doesn't have to hard-code values in the user's attributes, but can generate them on the fly without needing to update them. I think that would also help to bridge the gaps of support like Samba authentication for example.

**Describe the solution you'd like**
The Scope Mappings from OIDC basically 1:1 for LDAP.

**Describe alternatives you've considered**
I think there are some hacks you can do with sssd, but sometimes there just isn't the option to actually change the behavior of the client that much.