nvencoders don't support ultrafast and zerolatency
**Describe the bug**
Preset ultrafast and zerolatency are getting added regardless of the vcodec (except when using copy, the encoderOptions get removed in /src/accessories/camera.js:565). When using nvenc encoders, these presets have to be removed in order to use the nvenc encoder.

By setting the ffmpeg encoder options in camera.ui to an empty string or a whitespace (to remove the preset arguments), the plugin generates two empty bash arguments, which break the "-f rawvideo" argument before, so this is not an option.

**To Reproduce**
Use nvenc_h264 as encoder

**Expected behavior**
Working.

**Logs**
ffmpeg crashes with RC 1
```
[nvenc_h264 @ 0x5652fce04640] Unable to parse option value "zerolatency"
[nvenc_h264 @ 0x5652fce04640] Error setting option tune to value zerolatency.
[nvenc_h264 @ 0x55f4acb1cb40] Unable to parse option value "ultrafast"
[nvenc_h264 @ 0x55f4acb1cb40] Error setting option preset to value ultrafast.

```