use go.einride.tech/aip/pagination to reduce code dup

[glimchb]

see https://github.com/einride/aip-go/tree/master/pagination

see https://github.com/einride/aip-go/blob/d1496baa45a9dcbb474e8ad99c63387f6ce86c85/README.md#aip-132-standard-method-list

see

opi-evpn-bridge/pkg/evpn/evpn.go

Lines 83 to 106 in 71379e5

	const (
	maxPageSize = 250
	defaultPageSize = 50
	)
	switch {
	case pageSize < 0:
	return -1, -1, status.Error(codes.InvalidArgument, "negative PageSize is not allowed")
	case pageSize == 0:
	size = defaultPageSize
	case pageSize > maxPageSize:
	size = maxPageSize
	default:
	size = int(pageSize)
	}
	// fetch offset from the database using opaque token
	offset = 0
	if pageToken != "" {
	var ok bool
	offset, ok = pagination[pageToken]
	if !ok {
	return -1, -1, status.Errorf(codes.NotFound, "unable to find pagination token %s", pageToken)
	}
	log.Printf("Found offset %d from pagination token: %s", offset, pageToken)
	}