ProcessManager: Add a "Memory map" view to show a process's VM layout.

Fetch all the data from /proc/PID/vm for the selected process and show it
in a nice GTableView. :^)

Applications/ProcessManager/ProcessMemoryMapWidget.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <LibGUI/GWidget.h>
+
+class GTableView;
+
+class ProcessMemoryMapWidget final : public GWidget {
+    C_OBJECT(ProcessMemoryMapWidget);
+public:
+    explicit ProcessMemoryMapWidget(GWidget* parent);
+    virtual ~ProcessMemoryMapWidget() override;
+
+    void set_pid(pid_t);
+
+private:
+    GTableView* m_table_view { nullptr };
+    pid_t m_pid { -1 };
+};