use RClone to fetch SIS zip files from sftp server

[zqian]

Will provide scripts using the Rclone technology to:

• [x] download SIS zip and associated MD5.txt file from SFTP server into container
• [x] run sis_upload.rb script
• [x] archive the SIS zip and associated MD5.txt file into AWS S3 bucket once the SIS_upload.rb script is finished
• [x] remove SIS zip file and associated MD5.txt file from SFTP server
• [x] run sis_set_url.rb script
• [x] adjust sis_upload.rb script: removed the process for checking previous job status, since Canvas will put the SIS upload request into a queue and process sequentially; remove the process of archive zip files and write log files;
• [x] upgrade ruby to v2.7