fix: sample file path

Add native DLLs

Add C# port of vaapi_encode, vaapi_tarnscode

avio_reading - changed input_filename path

Add C# port of transcoding.c

Add C# port of remuxing.c

Add C# port of http_multiclient.c

Add C# port of scaling_video.c

Add C# port of metadata.c

Add C# port of filtering_audio.c

Add C# port of filter_audio.c

Add C# port of ffhash.c

Add C# port of encode_audio.c

Add C# port of decode_video.c

Add C# port of decode_audio.c