Shell: rewrite the whole shell to use tokens instead of raw strings

tab completion is still running with raw strings and that has to be
fixed in the future.

userspace/programs/Shell/Token.cpp

@@ -0,0 +1,52 @@
+#include "Token.h"
+
+#include <BAN/Debug.h>
+
+void Token::debug_dump() const
+{
+	switch (type())
+	{
+		case Type::EOF_:
+			dwarnln("Token <EOF>");
+			break;
+		case Type::Ampersand:
+			dprintln("Token <Ampersand>");
+			break;
+		case Type::Backslash:
+			dprintln("Token <Backslash>");
+			break;
+		case Type::CloseCurly:
+			dprintln("Token <CloseCurly>");
+			break;
+		case Type::CloseParen:
+			dprintln("Token <CloseParen>");
+			break;
+		case Type::Dollar:
+			dprintln("Token <Dollar>");
+			break;
+		case Type::DoubleQuote:
+			dprintln("Token <DoubleQuote>");
+			break;
+		case Type::OpenCurly:
+			dprintln("Token <OpenCurly>");
+			break;
+		case Type::OpenParen:
+			dprintln("Token <OpenParen>");
+			break;
+		case Type::Pipe:
+			dprintln("Token <Pipe>");
+			break;
+		case Type::Semicolon:
+			dprintln("Token <Semicolon>");
+			break;
+		case Type::SingleQuote:
+			dprintln("Token <SingleQuote>");
+			break;
+		case Type::String:
+			dprintln("Token <String \"{}\">", string());
+			break;
+		case Type::Whitespace:
+			dprintln("Token <Whitespace \"{}\">", string());
+			break;
+	}
+}