Add ability to track modifier state on the device

Remove LED sync source option and add keypress reporting while still working with devices that haven't been upgraded
We return the modifiers as the valid bitmask so that the VirtualKeyboard and InfoBar can represent the correct keys as down. This is important when we have strokes like Left-Control + Right-Control + Keypad-1 (used in switching KVMs and such).
Fix handling of modifier keys in client and also removed the extraneous resetKeyboardState.
Manage state to eliminate rerenders by judicious use of useMemo.
Centralized keyboard layout and localized display maps
Move keyboardOptions to useKeyboardLayouts
Added translations for display maps.
Add documentation on the legacy support.

Return the KeysDownState from keyboardReport
Clear out the hidErrorRollOver once sent to reset the keyboard to nothing down.
Handles the returned KeysDownState from keyboardReport
Now passes all logic through handleKeyPress.
If we get a state back from a keyboardReport, use it and also enable keypressReport because we now know it's an upgraded device.
Added exposition on isoCode management

Fix de-DE chars to reflect German E2 keyboard.
https://kbdlayout.info/kbdgre2/overview+virtualkeys

Ran go modernize
Morphs Interface{} to any
Ranges over SplitSeq and FieldSeq for iterating splits
Used min for end calculation remote_mount.Read
Used range 16 in wol.createMagicPacket
DID NOT apply the Omitempty cleanup.

Strong typed in the typescript realm.
Cleanup react state management to enable upgrading Zustand

ui/src/components/VirtualKeyboard.tsx

@@ -284,10 +284,6 @@ function KeyboardWrapper() {
                       preventMouseUpDefault={true}
                       stopMouseDownPropagation={true}
                       stopMouseUpPropagation={true}
-                      physicalKeyboardHighlight={true}
-                      physicalKeyboardHighlightPreventDefault={true}
-                      physicalKeyboardHighlightTextColor="black"
-                      physicalKeyboardHighlightBgColor="lightblue"
                     />
 
                     <div className="controlArrows">
@@ -305,10 +301,6 @@ function KeyboardWrapper() {
                         preventMouseUpDefault={true}
                         stopMouseDownPropagation={true}
                         stopMouseUpPropagation={true}
-                        physicalKeyboardHighlight={true}
-                        physicalKeyboardHighlightPreventDefault={true}
-                        physicalKeyboardHighlightTextColor="black"
-                        physicalKeyboardHighlightBgColor="lightblue"
                       />
                       <Keyboard
                         baseClass="simple-keyboard-arrows"
@@ -323,10 +315,6 @@ function KeyboardWrapper() {
                         preventMouseUpDefault={true}
                         stopMouseDownPropagation={true}
                         stopMouseUpPropagation={true}
-                        physicalKeyboardHighlight={true}
-                        physicalKeyboardHighlightPreventDefault={true}
-                        physicalKeyboardHighlightTextColor="black"
-                        physicalKeyboardHighlightBgColor="lightblue"
                       />
                     </div>
                     { /* TODO add optional number pad */ }

webrtc.go

@@ -23,6 +23,7 @@ type Session struct {
 	HidChannel               *webrtc.DataChannel
 	DiskChannel              *webrtc.DataChannel
 	shouldUmountVirtualMedia bool
+	rpcQueue                 chan webrtc.DataChannelMessage
 }
 
 type SessionConfig struct {
@@ -106,6 +107,12 @@ func newSession(config SessionConfig) (*Session, error) {
 		return nil, err
 	}
 	session := &Session{peerConnection: peerConnection}
+	session.rpcQueue = make(chan webrtc.DataChannelMessage, 256)
+	go func() {
+		for msg := range session.rpcQueue {
+			onRPCMessage(msg, session)
+		}
+	}()
 
 	peerConnection.OnDataChannel(func(d *webrtc.DataChannel) {
 		scopedLogger.Info().Str("label", d.Label()).Uint16("id", *d.ID()).Msg("New DataChannel")
@@ -113,7 +120,8 @@ func newSession(config SessionConfig) (*Session, error) {
 		case "rpc":
 			session.RPCChannel = d
 			d.OnMessage(func(msg webrtc.DataChannelMessage) {
-				go onRPCMessage(msg, session)
+				// Enqueue to ensure ordered processing
+				session.rpcQueue <- msg
 			})
 			triggerOTAStateUpdate()
 			triggerVideoStateUpdate()
@@ -189,6 +197,11 @@ func newSession(config SessionConfig) (*Session, error) {
 			if session == currentSession {
 				currentSession = nil
 			}
+			// Stop RPC processor
+			if session.rpcQueue != nil {
+				close(session.rpcQueue)
+				session.rpcQueue = nil
+			}
 			if session.shouldUmountVirtualMedia {
 				if err := rpcUnmountImage(); err != nil {
 					scopedLogger.Warn().Err(err).Msg("unmount image failed on connection close")