Fixed channel icon conflict when populating the database from a XMLTV source

Based on the remote filenames of the icons, conflicts can arise, causing a mess:

  <icon src="https://static.te.../stations/308/icon320_light.png?v2023_48_0"/>
  <icon src="https://static.te.../stations/58/icon320_light.png?v2023_48_0"/>
  <icon src="https://static.te.../stations/383/icon320_light.png?v2023_48_0"/>

These cases generate the same icon filename 'icon320_light.png?v2023_48_0'.

The proposed solution no longer uses the original filename; it now generates a
user-friendly name from the source identifier of channel (sourceId + xmltvId),
followed by the remote name.
This way, the generated name can no longer conflict with that of another channel,
and it is easily identifiable by the user.

  <source_id>_<xmltv_id>_<remotename>

Now downloaded icon names from xmltv source look like the following.

  1_TF1SeriesFilms.fr_icon320_light.png?v2023_48_0
  1_LEquipe21.fr_icon320_light.png?v2023_48_0
  1_6ter.fr_icon320_light.png?v2023_48_0

Author: janbar

mythtv/programs/mythfilldatabase/channeldata.cpp

@@ -211,8 +211,13 @@ void ChannelData::handleChannels(int id, ChannelInfoList *chanlist) const
 
         if (!(*i).m_icon.isEmpty())
         {
-            QDir remotefile = QDir((*i).m_icon);
-            QString filename = remotefile.dirName();
+            QString remotename = QDir((*i).m_icon).dirName();
+            // Define an unique icon filename for this channel and xmltv source
+            // The most obvious format is <source_id>_<xmltv_id>_<remotename>
+            QString filename(QString::number(id));
+            filename.append("_").append((*i).m_xmltvId);
+            filename.append("_").append(remotename);
+            filename.remove(QRegularExpression("[ \\\\/\\:\\*\\[\\]\\(\\)]"));
 
             localfile = fileprefix + filename;
             QFile actualfile(localfile);