Invoke with `bricks sync SRC DST`.
In bundle context `SRC` and `DST` arguments are taken from bundle configuration.
This PR adds `bricks bundle sync` to disambiguate between the two.
Once the VS Code extension is bundle aware they can again be consolidated.
Consolidating them today would regress the VS Code experience if a
`bundle.yml` file is present in the file tree.
Pieter Noordhuis