Support migration patch resource used to manage a nested resource

[ms-henglu]

The nested resource has its own resource id, it's different from the azurem resource's id pattern.

For example, SOA record's id looks like
/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Network/dnsZones/{zoneName}/{recordType}/{relativeRecordSetName}

But its target resource azurerm_dns_zone's id pattern looks like
/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Network/dnsZones/{zoneName}

So we need to manually maintain this mapping in https://github.com/ms-henglu/azurerm-restapi-to-azurerm/blob/master/azurerm/loader/loader_hardcode.go