We don't need to support any complex queries on /education (yet?). And if we would need
to add support for $search, $filter, $expand or $select we should pass the parsed odata Query
instead of the raw url.Values struct.
As described in #5410: add support for updating educationClass properties.
This adds the `UpdateEducationClass` to the `EducationBackend` interface,
and implements it on the `ErrEducationBackend` and `LDAP` backends.
It also alters `PatchEducationClass` to call the `UpdateEducationClass` method.
Closes#5410
* Renamed files for consistency reasons
err_school.go implements the full education interface not just schools.
ldap_school.go renamed to ldap_education_school.go for making it
consistent with ldap_education_user.go
* graph: Add stubs for education/classes endpoints
The acutal backend implementations are still empty.
Ralf Haferkamp