[GH-1111] Handle environments in AOU file paths

[samanehsan]

Purpose

https://broadinstitute.atlassian.net/browse/GH-1111

Changes

• Change the env parameter to accept "staging" in addition to "dev" and "prod".
• Only cleanup files in the input bucket from the env directory. For example, running the script with the "staging" environment will clean up files in the staging directory of the dev-aou-arrays-input bucket. This is required because dev and staging could have samples with the same exact chip name, chip well barcode and analysis version.
• Add "staging" environment to keep_files.

Review Instructions

• No instructions.

[tbl3rd]

I hope the overlap of dev and staging won't confuse things more.

[samanehsan]

I realized since the script leaves behind the "latest" analysis version, it will need to handle both the old and new file paths...fixing this now! Actually it'll probably be easier to update the old file paths instead of making the script more complicated.