Let the terminal panel dock to any part of the window

Summary:
BUG: 362593

Just what it says: Let the terminal panel sit on the left or right side of the window.

Test Plan:
Tested in KDE Neon:
- Opened terminal panel, unlocked widgets, and tried to drag it to the right or left side of the window: I can
- Put terminal panel on right side, quit Dolphin and opened Dolphin again: terminal panel appears on the right as expected
- Put terminal panel on right side, closed terminal panel, quit Dolphin, opened Dolphin, and opened the terminal panel again: terminal panel appears on the right as expected
- Removed dolphinrc file and opened terminal panel: appears on the bottom

{F5682428}

Reviewers: #dolphin

Subscribers: elvisangelaccio, anthonyfieroni, cfeck

Differential Revision: https://phabricator.kde.org/D10189

src/dolphinmainwindow.cpp

@@ -1278,7 +1278,6 @@ void DolphinMainWindow::setupDockWidgets()
         DolphinDockWidget* terminalDock = new DolphinDockWidget(i18nc("@title:window Shell terminal", "Terminal"));
         terminalDock->setLocked(lock);
         terminalDock->setObjectName(QStringLiteral("terminalDock"));
-        terminalDock->setAllowedAreas(Qt::TopDockWidgetArea | Qt::BottomDockWidgetArea);
         m_terminalPanel = new TerminalPanel(terminalDock);
         m_terminalPanel->setCustomContextMenuActions({lockLayoutAction});
         terminalDock->setWidget(m_terminalPanel);