Add linting for copyright and unused usings (#1416)

* Add linting for copyright and unused usings

* Add one more + comment

* Enforce in build and fix errors

* Fix build

src/Microsoft.SqlTools.ResourceProvider.Core/Contracts/Account.cs

@@ -68,13 +68,13 @@ namespace Microsoft.SqlTools.ResourceProvider.Core.Contracts
     public class ProviderSettings
     {
         /// <summary>
-        /// Display name of the provider 
+        /// Display name of the provider
         /// </summary>
         public string DisplayName;
 
         /// <summary>
         /// ID of the provider
-        /// </summary>    
+        /// </summary>
         public string Id;
         /// <summary>
         /// Settings for the provider itself

src/Microsoft.SqlTools.ResourceProvider.Core/Contracts/FirewallRule.cs

@@ -28,7 +28,7 @@ namespace Microsoft.SqlTools.ResourceProvider.Core.Contracts
         /// </summary>
         public Account Account { get; set; }
         /// <summary>
-        /// Per-tenant token mappings. Ideally would be set independently of this call, but for 
+        /// Per-tenant token mappings. Ideally would be set independently of this call, but for
         /// now this allows us to get the tokens necessary to find a server and open a firewall rule
         /// </summary>
         public Dictionary<string,AccountSecurityToken> SecurityTokenMappings { get; set; }
@@ -47,7 +47,7 @@ namespace Microsoft.SqlTools.ResourceProvider.Core.Contracts
         /// End of the IP address range
         /// </summary>
         public string EndIpAddress { get; set; }
-  
+
     }
 
     public class CreateFirewallRuleResponse : TokenReliantResponse
@@ -61,7 +61,7 @@ namespace Microsoft.SqlTools.ResourceProvider.Core.Contracts
     public class CanHandleFirewallRuleRequest
     {
         public static readonly
-            RequestType<HandleFirewallRuleParams, HandleFirewallRuleResponse> Type = 
+            RequestType<HandleFirewallRuleParams, HandleFirewallRuleResponse> Type =
             RequestType<HandleFirewallRuleParams, HandleFirewallRuleResponse>.Create("resource/handleFirewallRule");
     }