Rename Thumbnail operator to "Proxy" Operator

[gmarchand]

Describe the bug I want to only create translated subtitles of my video assets and integrate this workflow to my Media Supply Chain. I used the workflow defined in https://github.com/aws-samples/aws-media-insights-content-localization

I disable operators like thumbnail, because I don't need thumbnail But TranscribeVideo operation doesn't work, and the workflow fails because it doesn't find Audio proxy.

Audio proxy is made by the "thumbnail" operator. So this operator is misnamed. Its name would be "proxy"

To Reproduce The thumbnail operator create thumbnails with MediaConvert. But it also creates Audio Proxy. https://github.com/awslabs/aws-media-insights-engine/blob/development/source/operators/thumbnail/start_thumbnail.py#L139

Here is my config with Content Localization workflow

{
"Name":"VODSubtitlesVideoWorkflow",
"Input": 
    {"Media":
        {"Video":
            {
                "S3Bucket": "mybucket",
                "S3Key":"myvideo.mp4"
            }
        }
    },
"Configuration": {
        "TranslateStage2": {
            "Translate": {
                "MediaType": "Text",
                "Enabled": false
            },
            "TranslateWebCaptions": {
                "MediaType": "MetadataOnly",
                "Enabled": true,
                "TargetLanguageCodes": [
                    "so"
                ],
                "SourceLanguageCode": "fr",
                "TerminologyNames": [],
                "ParallelDataNames": []
            }
        },
        "defaultPrelimVideoStage2": {
            "Thumbnail": {
                "ThumbnailPosition": "10",
                "MediaType": "Video",
                "Enabled": false
            },
            "Mediainfo": {
                "MediaType": "Video",
                "Enabled": false
            }
        },
        "CaptionFileStage2": {
            "PollyWebCaptions": {
                "MediaType": "MetadataOnly",
                "Enabled": true,
                "SourceLanguageCode": "fr"
            },
            "WebToSRTCaptions": {
                "MediaType": "MetadataOnly",
                "Enabled": true,
                "TargetLanguageCodes": [
                    "so",
                    "fr"
                ]
            },
            "WebToVTTCaptions": {
                "MediaType": "MetadataOnly",
                "Enabled": true,
                "TargetLanguageCodes": [
                    "so",
                    "fr"
                ]
            }
        },
        "WebCaptionsStage2": {
            "WebCaptions": {
                "MediaType": "MetadataOnly",
                "Enabled": true,
                "SourceLanguageCode": "fr"
            }
        },
        "defaultAudioStage2": {
            "TranscribeVideo": {
                "MediaType": "Audio",
                "Enabled": true,
                "TranscribeLanguage": "fr-FR"
            }
        },
        "defaultVideoStage2": {
            "faceDetection": {
                "MediaType": "Video",
                "Enabled": false
            },
            "textDetection": {
                "MediaType": "Video",
                "Enabled": false
            },
            "celebrityRecognition": {
                "MediaType": "Video",
                "Enabled": false
            },
            "GenericDataLookup": {
                "MediaType": "Video",
                "Enabled": false
            },
            "labelDetection": {
                "MediaType": "Video",
                "Enabled": false
            },
            "personTracking": {
                "MediaType": "Video",
                "Enabled": false
            },
            "Mediaconvert": {
                "MediaType": "Video",
                "Enabled": false
            },
            "faceSearch": {
                "MediaType": "Video",
                "Enabled": false,
                "CollectionId": "undefined"
            }
        },
        "defaultTextStage2": {
            "ComprehendEntities": {
                "MediaType": "Text",
                "Enabled": false
            },
            "ComprehendKeyPhrases": {
                "MediaType": "Text",
                "Enabled": false
            }
        }
    }
}

Expected behavior A clear and concise description of what you expected to happen.

Please complete the following information about the solution:

• [ ] Version :2.0.5