Add telecomms system (#14486)

Content.Shared/Radio/Components/TelecomServerComponent.cs

@@ -1,6 +1,12 @@
 namespace Content.Shared.Radio.Components;
 
+/// <summary>
+/// Entities with <see cref="TelecomServerComponent"/> are needed to transmit messages using headsets. 
+/// They also need to be powered by <see cref="ApcPowerReceiverComponent"/>
+/// have <see cref="EncryptionKeyHolderComponent"/> and filled with encryption keys
+/// of channels in order for them to work on the same map as server.
+/// </summary>
 [RegisterComponent]
 public sealed class TelecomServerComponent : Component
 {
-}
+}