feat(api): support utf8 output in websocket endpoints

* change TCPConnToWebsocketConn read function to ReadRune

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Update websocket_exec.go

* Delete Project_Default.xml

* Delete modules.xml

* Delete portainer.iml

* Delete vcs.xml

* Delete workspace.xml

* Delete exec.go

* change TCPConnToWebsocketConn read function to ReadRune

* Apply suggestions from code review

Co-Authored-By: Anthony Lapenna <lapenna.anthony@gmail.com>

* Update stream.go

api/http/handler/websocket/stream.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"github.com/gorilla/websocket"
 	"net"
+	"unicode/utf8"
 )
 
 func streamFromWebsocketConnToTCPConn(websocketConn *websocket.Conn, tcpConn net.Conn, errorChan chan error) {
@@ -26,15 +27,33 @@ func streamFromTCPConnToWebsocketConn(websocketConn *websocket.Conn, br *bufio.R
 	for {
 		out := make([]byte, 2048)
 		_, err := br.Read(out)
+		processedOutput := validString(string(out[:]))
 		if err != nil {
 			errorChan <- err
 			break
 		}
 
-		err = websocketConn.WriteMessage(websocket.TextMessage, out)
+		err = websocketConn.WriteMessage(websocket.TextMessage, []byte(processedOutput))
 		if err != nil {
 			errorChan <- err
 			break
 		}
 	}
 }
+
+func validString(s string) string {
+	if !utf8.ValidString(s) {
+		v := make([]rune, 0, len(s))
+		for i, r := range s {
+			if r == utf8.RuneError {
+				_, size := utf8.DecodeRuneInString(s[i:])
+				if size == 1 {
+					continue
+				}
+			}
+			v = append(v, r)
+		}
+		s = string(v)
+	}
+	return s
+}