Pass variables from high level graph to low-level level one

[vharitonsky]

If low-level graph field is accepting options for entity filter, there should a possibility to pass the variables down from top level graph. This will allow to avoid unnecessary query and optimize db queries.
Example:
High level graph:

Field('regionName', String, company_sg.c(
            get_company_region(
                S.this.address,
                each(S.branch, S.this.branches, S.branch.address.region_id),
                S.regionId
            )
        ), options=[Option('regionId', Optional[Integer], default=None)]),

This field uses region as a way to filter branches on the client side. If we could pass the variable, we could filter them server side limiting the amount of entities we need to process to zero in most common cases

Field('regionName', String, company_sg.c(
            get_company_region(
                S.this.address,
                each(S.branch, S.this.branches(S.regionId), S.branch.address.region_id),
                S.regionId
            )
        ), options=[Option('regionId', Optional[Integer], default=None)]),