Log directory operations

[tomwrobel]

It would be useful to be able to:

• get a list of files in the logs directory
• write a file to the logs directory
• ?delete a file from the logs directory
• append to a file in the logs directory

This is not terribly high priority, as all of these can be performed adequately with system commands. However, I think there is use (long term) in supporting this via a client call. If nothing else, it means that we can limit the user who are writing into the OCFL root (and digital preservation agents would fall into this category)

Possible commands:

• ocfl ls {object} -t logs: list all files in the logs directory
• ocfl cp {object} {file} -t logs: copy a file to the logs directory
• oclf rm -f {object} {filepath from /logs} -t logs remove a file from the logs directory (if -t logs is not specified, this should be an error)
• ocfl cp >> {object} {filepath from /logs} -t logs: append to a file in the logs directory