add options for SDSC and EC2 patchers

[oliche]

During the patching of the wheel data, I needed some more control of patching using EC2 and SDSC.

• SDSC patcher operates on symlinks, and if one of the input files is modified, this directly impacts the original data. I have set an assertion that enforces distinct input and output datasets
• the EC2 patcher didn't check file hashes on checking local data, I've set it to true by default and provided an option to opt-out for bulky input data such as spike sorting. task.run(hash_files=False)