Docker: Provide a means to select search paths for auto-detection

A combobox in the device dialog to select between the (docker image's)
system path and a semicolon-separated set of user defined paths.

Use it for cmake and gdb detection; qmake and toolchains currently missing.

Change-Id: I3c478ca914a1bf02dcb69ebcb9ea6e358d24aaf9
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/debugger/debuggerplugin.h

@@ -26,10 +26,11 @@
 #pragma once
 
 #include "debugger_global.h"
+
 #include <extensionsystem/iplugin.h>
+#include <utils/filepath.h>
 
 namespace ProjectExplorer { class RunControl; }
-namespace Utils { class FilePath; }
 
 namespace Debugger {
 namespace Internal {
@@ -59,7 +60,7 @@ private:
     Q_SLOT void getEnginesState(QByteArray *json) const;
 
     // Called from DockerDevice
-    Q_SLOT void autoDetectDebuggersForDevice(const Utils::FilePath &deviceRoot,
+    Q_SLOT void autoDetectDebuggersForDevice(const Utils::FilePaths &searchPaths,
                                              const QString &detectionId,
                                              QString *logMessage);
     Q_SLOT void removeDetectedDebuggers(const QString &detectionId, QString *logMessage);