Add ability to provide chunks to uploader

Type of issue

• Bug report
• Feature request

Uploader type

• Traditional
• S3
• Azure

Feature request details

I think it is better to provide a use case. You have a video stream recorder(webcam, audio, desktop etc.). During recording it generates Blobs which must be uploaded to S3. Currently, Fineuploader suppots only complete files which will be splitted to chunks and uploaded. Request is to provide more low level API for multipart chunked uploading, for example:

let fileId = uploaderInstance.createMultipartUpload();
uploaderInstance.addChunk(fileId, blob1);
uploaderInstance.addChunk(fileId, blob2);
uploaderInstance.addChunk(fileId, blob3);
uploaderInstance.completeMultipartUpload(fileId);