Auto-configuration of LDAP's `LdapTemplate` is currently a part of
`LdapDataAutoConfiguration` which is conditional of presence of
`LdapRepository` (i.e. Spring Data LDAP). This arrangement isn't ideal
since the `LdapTemplate` is a part of Spring LDAP project, and therefore
should not be tied to Spring Data LDAP.

This commit improves and simplifies LDAP auto-configuration by moving
`LdapTemplate` configuration to `LdapAutoConfiguration`. Consequently,
`LdapDataAutoConfiguration` is not needed anymore and is removed.

See gh-13136