Update documentation for ibm_resource_tag (IBM-Cloud#5700)

* Deprecated ibm_resource_access_tag in favor of ibm_iam_access_tag

* changes

* Fix

* Changed resource to speed up tests

* fix

* PR changes

* PR changes

* Added new context functions.
Now the code handles the error in the response on resource tags calls.

* Fixed 5635

* Fix

* Fixed

* Removed logs line

* Updated doc

* Fix

* Fix PR

website/docs/r/resource_tag.html.markdown

@@ -44,7 +44,7 @@ The `ibm_resource_tag` resource provides the following [Timeouts](https://www.te
 Review the argument references that you can specify for your resource.
 
 - `resource_id` - (Required, String) The CRN of the resource on which the tags is be attached.
-- `resource_type` - (Optional, String) The resource type on which the tags should be attached.
+- `resource_type` - (Optional, String) The resource type on which the tags should be attached. This is valid for Classic Infrastructure resources only. The `resource_type` allowed values are: `SoftLayer_Virtual_DedicatedHost`, `SoftLayer_Hardware`, `SoftLayer_Hardware_Server`, `SoftLayer_Network_Application_Delivery_Controller`, `SoftLayer_Network_Vlan`, `SoftLayer_Network_Vlan_Firewall`, `SoftLayer_Network_Component_Firewall`, `SoftLayer_Network_Firewall_Module_Context`, `SoftLayer_Virtual_Guest`. A wrong value would result in an error in the `terraform apply` command.
 - `tag_type` - (Optional, String) Type of the tag. Supported values are: `user` or `access`. The default value is user.
 - `tags` - (Required, Array of strings) List of tags associated with resource instance.
 - `replace` - (Optional, Bool) If true, it indicates that the attaching operation is a replacement operation