fix(nw): add guidance for resource naming (#4014)

Author: RoRoJ

macros/vpc/network-resource-naming.mdx

@@ -0,0 +1,7 @@
+---
+macro: network-resource-naming
+---
+
+<Message type="note">
+The resource name can only include alphanumerical characters and dashes.
+</Message>

macros/vpc/pn-naming.mdx

@@ -3,5 +3,5 @@ macro: pn-naming
 ---
 
 <Message type="note">
-Avoid using a **T**op **L**evel **D**omain as your Private Network name, as this can cause addressing conflicts. For example, do not call your Private Network `dev`, `cloud` or `com`. For a complete reference of TLDs to avoid, see the full list provided by [IANA](https://data.iana.org/TLD/tlds-alpha-by-domain.txt). Read more about this issue in our [dedicated documentation](/network/vpc/troubleshooting/pn-name/).
+The resource name can only include alphanumeric characters and dashes. Avoid using a **T**op **L**evel **D**omain as your Private Network name, as this can cause addressing conflicts. For example, do not call your Private Network `dev`, `cloud` or `com`. For a complete reference of TLDs to avoid, see the full list provided by [IANA](https://data.iana.org/TLD/tlds-alpha-by-domain.txt). Read more about this issue in our [dedicated documentation](/network/vpc/troubleshooting/pn-name/).
 </Message>

network/public-gateways/how-to/create-a-public-gateway.mdx

@@ -29,6 +29,7 @@ categories:
     - Choose a **Public Gateway Type**, which impacts the pricing and bandwidth of your gateway.
     - Choose an **IP**. You can choose to assign one of your existing flexible IPs to your Public Gateway, or create and assign a new public IP. 
     - Choose a **Name** for your Public Gateway, and, optionally, tags.
+         <Macro id="network-resource-naming"/>
     - Verify the **Estimated Cost** of your Public Gateway, based on the specifications you chose.
 4. Click **Create Public Gateway** to finish.
 

network/public-gateways/quickstart.mdx

@@ -29,6 +29,7 @@ categories:
     - Choose a **Public Gateway Type**, which impacts the pricing and bandwidth of your gateway.
     - Choose an **IP**. You can choose to assign one of your existing flexible IPs to your Public Gateway, or create and assign a new public IP. 
     - Choose a **Name** for your Public Gateway, and, optionally, tags.
+        <Macro id="network-resource-naming"/>
     - Verify the **Estimated Cost** of your Public Gateway, based on the specifications you chose.
 4. Click **Create Public Gateway** to finish.
 

network/vpc/how-to/create-vpc.mdx

@@ -52,6 +52,8 @@ If you want to create more VPCs beyond the default ones created for you, you can
 
 4. Enter a **name** for your VPC (or use the wand icon to generate a random name). Optionally, you can also add **tags** to help organize your VPCs. Each tag should be separated by a space.
 
+    <Macro id="network-resource-naming"/>
+
 5. Enter a name for the **Private Network** that will be automatically created in this new VPC. Alternatively, click the wand icon to generate a name automatically.
 
     <Message type="note">