Allow the possibility to have multiple LDAP servers

Configuration should work similar to the way `dataSources` configuraiton work. That it is to say you could define common configuration for every ldap sever as you currently do for a single one and then have multiple LDAP servers which use the common configuration and the values they override.

Start by locating the LDAP configuration and the existing dataSources configuration, then compare how common settings and per-entry overrides are represented. Define the expected configuration shape for multiple LDAP servers and verify that each server inherits common values while applying its overrides; the payload names no files or tests to run.

Written by the indexing model from the issue text.