Data sync: allow more advanced workdir and output specs

[dberenbaum]

It would be great for workdir/output to support:

• Lists of multiple paths
• Globs or regexes

[0x2b3bfa0]

Storage syntax can be easily extended to support rclone filters to include and exclude several paths or globs from data transfers:

• task: make workdir.output more intuitive #414 (comment)

[dacbd]

+1 for a exclude option,

storage {
  workdir = "."
  exclude = [
    ".dvc/cache",
    "venv"
  ]
  output = "./reports"
}

[casperdcl]

Quick note: exclude should be a list[str] relative to workdir