WIP: prototype scripts for administrating Arcyd
Revert "WIP: prototype scripts for administrating Arcyd"

This reverts commit 8fef7a0e8531b4d711fdf813cd4fa120cfffff4d.
add doc/design/arcyd_cli.txt
Arcyd: fix doc: spell Arcyd correctly
WIP: phlsys_fs: add 'ensure_dir', 'write_text_file'

Make it easy to write text files and other files at arbitrary paths
without having to worry about creating the intermediate directories
along the path.
WIP: Arcyd: add 'init' command
WIP: arcyd start
abdi_processargs: nicer cli argument strings
WIP: arcyd add-phabricator
WIP: arcyd add-repo