Consolidate all services to use the Reva config struct for the shared package.
This works because all services (except 'notifications', 'thumbnails' and
'webdav') where using the same config keys and environment variables for
setting the reva gateway.
When expanding members of an LDAP group we did two group lookup per
Group. This can be avoided by expanding the members right from the
Group entry of the first query.
This also add some more unit test coverage, especially to the expand/select
group member test cases.
By default the graph API will now use the LDAP Password Modify Extended
Operation for setting user passwords. By this we make sure that the
LDAP server can e.g. properly hash the password with and algorithm that
it supports.
This can be reverted to the old behaviour (using "normal" LDAP modify
requests) by setting GRAPH_LDAP_SERVER_USE_PASSWORD_MODIFY_EXOP=false
Fixes: #3778
