add watermark support to experimental transcoder logic (#654)

* wip

* fix songs again

* don't use lists of video and audio input files

* test concat command output

* move concat pipeline

* start to use ffmpeg state

* add ffmpeg state and audio state

* audio state is required

* attach input options directly to input files

* move filters to input files

* add watermark support

ErsatzTV.Core/Interfaces/FFmpeg/IFFmpegProcessService.cs

@@ -4,6 +4,7 @@ using System.Threading.Tasks;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.Domain.Filler;
 using ErsatzTV.Core.FFmpeg;
+using ErsatzTV.FFmpeg.State;
 using LanguageExt;
 
 namespace ErsatzTV.Core.Interfaces.FFmpeg
@@ -56,7 +57,7 @@ namespace ErsatzTV.Core.Interfaces.FFmpeg
             string videoPath,
             bool boxBlur,
             Option<string> watermarkPath,
-            ChannelWatermarkLocation watermarkLocation,
+            WatermarkLocation watermarkLocation,
             int horizontalMarginPercent,
             int verticalMarginPercent,
             int watermarkWidthPercent);