Persist a default browse directory for file dialogs, if none is provided

* This provides a slightly more sensible default than the application working
  directory.
* The default is shared across all dialogs and open/save.

qrenderdoc/Code/Interface/PersistantConfig.cpp

@@ -287,6 +287,8 @@ bool PersistantConfig::Load(const rdcstr &filename)
 
   RENDERDOC_SetConfigSetting("Disassembly_FriendlyNaming", ShaderViewer_FriendlyNaming ? "1" : "0");
 
+  RDDialog::DefaultBrowsePath = LastFileBrowsePath;
+
   // localhost should always be available as a remote host
   bool foundLocalhost = false;
 
@@ -396,6 +398,8 @@ bool PersistantConfig::Save()
 
   RENDERDOC_SetConfigSetting("Disassembly_FriendlyNaming", ShaderViewer_FriendlyNaming ? "1" : "0");
 
+  LastFileBrowsePath = RDDialog::DefaultBrowsePath;
+
   return Serialize(m_Filename);
 }
 

qrenderdoc/Code/Interface/PersistantConfig.h

@@ -167,6 +167,8 @@ DECLARE_REFLECTION_STRUCT(BugReport);
                                                                                            \
   CONFIG_SETTING_VAL(public, QString, rdcstr, LastCaptureFilePath, "")                     \
                                                                                            \
+  CONFIG_SETTING_VAL(public, QString, rdcstr, LastFileBrowsePath, "")                      \
+                                                                                           \
   CONFIG_SETTING(public, QVariantList, rdcarray<rdcstr>, RecentCaptureFiles)               \
                                                                                            \
   CONFIG_SETTING_VAL(public, QString, rdcstr, LastCapturePath, "")                         \
@@ -332,6 +334,12 @@ For more information about some of these settings that are user-facing see
 
   The path to the last capture to be opened, which is useful as a default location for browsing.
 
+.. data:: LastFileBrowsePath
+
+  The path to the last file browsed to in any dialog. Used as a default location for all file
+  browsers without another explicit default directory (such as opening capture files - see
+  :data:`LastCaptureFilePath`).
+
 .. data:: RecentCaptureFiles
 
   A ``list`` of ``str`` with the recently opened capture files.