[mythtv] Adding booleans to disable icons

Allows to disable channel, fanart, and recording icons for lower powered systems like RPi.
[mythtv] Adding new settings to handle icons visibility
[mythtv] Adding dummy icon for recording
[mythtv] Adding dummy icon for channel
[mythtv] Disables fanart, thumbnails, icons depending of settings

- FileOps will provides tiny icon when options are disable