add swift sub commands to easy file management

users who uploaded their complex folder structure using the swift upload command find it difficult to navigate the flat object structure

/folder1/folder2/folder3/object

The swift list command just shows all objects in a container and has no concept of pseudo directories. Use is complicated and unnatural as list command always needs to be filtered with grep

solution: implement 5 new sub commands:

swift cd -> changes to different pseudo directory and exports the current pseudo directory in an env var. (e.g. SWIFT_CURRENT_DIR)

swift ls -> lists objects only at the current pseudo directory level SWIFT_CURRENT_DIR, lists the container root if unset (specifically all strings left of the leftmost slash / )

swift rm -> removes objects only at the current pseudo dir SWIFT_CURRENT_DIR (and below if used with -rf)

swift mkdir -> creates new pseudo directory below SWIFT_CURRENT_DIR

swift cp -> copy object relative to current SWIFT_CURRENT_DIR

see https://github.com/FredHutch/swift-commander for workaround using shell wrapper