Release v20.4

Release Notes:

• Upgrade OpenVINO to v2020.2
• Upgrade FFmpeg video analytics plugin to v0.5
• Upgrade GStreamer video analytics plugin to v1.0
• Upgrade SVT AV1 to v0.8.3
• Upgrade SVT AV1 CDN patch to v0.4
• Upgrade SVT VP9 to v0.2.0
• Update nginx to 1.16.1
• Automated Dockerhub README generation and uploading
• Use OpenVINO template to generate hddldaemon image
• GST VAAPI to include lock patch
• Add dldt tools to dev images
• Misc cmake/make script improvements
• Enhance setup_weavenet.sh for multiple identical VCAC-A nodes

Bug fixes:

• Fix ogg and vorbis resource server down issue. #493
• Remove sudo in build scripts #486
• Gvaidentify fix for gst video anlytics #482
• Qat chown for build issue fix. #480
• GST vaapi to include lock patch #456
• Fix Warning: excess arguments to builtin ifelse ignored. #454
• Optimized and fix issue for generate_readme.py #453
• Fixing inconsistent kafka issue #452
• Fix checkinstall error #445
• Fix media driver build failure caused by gcc upgraded to 7.5.0
• Dldt protobuf fix for removing redundant protobuf #442
• hddl: fix ov_hddl_init restart issues #433
• Fix swarm script for multiple VCAC-As #429