feat: process images/videos in parallel with multiprocessing

[ptpt]

❯ du -sh ~/Downloads/MyGoProVideos
 99G	/Users/taopeng/Downloads/MyGoProVideos

Before

❯ time python3 -m mapillary_tools.commands process ~/Downloads/MyGoProVideos/
Extracting geotags from images: 100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 954/954 [00:04<00:00, 196.96images/s]
Extracting GPS tracks from videos: 100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 51/51 [03:53<00:00,  4.59s/videos]
2023-05-22 16:38:52,715 - INFO    - Validating 1005 metadatas
2023-05-22 16:39:00,045 - INFO    - Checking upload status for 1005 metadatas
2023-05-22 16:39:00,744 - INFO    - Check the description file for details: /Users/taopeng/Downloads/MyGoProVideos/mapillary_image_description.json
2023-05-22 16:39:00,750 - INFO    -       51 gopro(s) read in total
2023-05-22 16:39:00,750 - INFO    - 	       27 gopro(s) are ready to be uploaded
2023-05-22 16:39:00,750 - ERROR   - 	       22 gopro(s) failed due to MapillaryGPXEmptyError
2023-05-22 16:39:00,750 - ERROR   - 	        1 gopro(s) failed due to MapillaryStationaryVideoError
2023-05-22 16:39:00,750 - WARNING - 	        1 gopro(s) skipped due to MapillaryUploadedAlreadyError
2023-05-22 16:39:00,750 - INFO    -      954 image(s) read in total
2023-05-22 16:39:00,750 - INFO    - 	      954 image(s) are ready to be uploaded
2023-05-22 16:39:00,751 - ERROR   - MapillaryProcessError: Failed to process 23 files. To skip these errors, specify --skip_process_errors
python3 -m mapillary_tools.commands process ~/Downloads/MyGoProVideos/  234.23s user 7.40s system 97% cpu 4:07.52 total

Now

❯ time python3 -m mapillary_tools.commands process ~/Downloads/MyGoProVideos/
Extracting geotags from images: 100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 954/954 [00:01<00:00, 727.81images/s]
Extracting GPS tracks from videos: 100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 51/51 [00:47<00:00,  1.08videos/s]
2023-05-22 16:41:11,687 - INFO    - Validating 1005 metadatas
2023-05-22 16:41:18,542 - INFO    - Checking upload status for 1005 metadatas
2023-05-22 16:41:19,130 - INFO    - Check the description file for details: /Users/taopeng/Downloads/MyGoProVideos/mapillary_image_description.json
2023-05-22 16:41:19,136 - INFO    -       51 gopro(s) read in total
2023-05-22 16:41:19,136 - INFO    - 	       27 gopro(s) are ready to be uploaded
2023-05-22 16:41:19,136 - ERROR   - 	       22 gopro(s) failed due to MapillaryGPXEmptyError
2023-05-22 16:41:19,136 - ERROR   - 	        1 gopro(s) failed due to MapillaryStationaryVideoError
2023-05-22 16:41:19,136 - WARNING - 	        1 gopro(s) skipped due to MapillaryUploadedAlreadyError
2023-05-22 16:41:19,136 - INFO    -      954 image(s) read in total
2023-05-22 16:41:19,136 - INFO    - 	      954 image(s) are ready to be uploaded
2023-05-22 16:41:19,136 - ERROR   - MapillaryProcessError: Failed to process 23 files. To skip these errors, specify --skip_process_errors
python3 -m mapillary_tools.commands process ~/Downloads/MyGoProVideos/  265.89s user 10.66s system 484% cpu 57.047 total