Bicep file reports linter warnings

[PatAltimore]

When using the bicep deployment file https://github.com/Azure/iotedge-vm-deploy/blob/main/edgeDeploy.bicep, linter warnings are reported.

/home/pat/main.bicep(58,5) : Warning decompiler-cleanup: The name of variable 'networkSecurityGroupName_var' appears to have originated from a naming conflict during a decompilation from JSON. Consider renaming it and removing the suffix (using the editor's rename functionality). [https://aka.ms/bicep/linter/decompiler-cleanup]
/home/pat/main.bicep(131,13) : Warning use-resource-id-functions: If property "id" represents a resource ID, it must use a symbolic resource reference, be a parameter or start with one of these functions: extensionResourceId, guid, if, reference, resourceId, subscription, subscriptionResourceId, tenantResourceId. Found nonconforming expression at id -> subnet1Ref [https://aka.ms/bicep/linter/use-resource-id-functions]
/home/pat/main.bicep(151,65) : Warning simplify-json-null: Simplify json('null') to null [https://aka.ms/bicep/linter/simplify-json-null]