cli: allow specifying target dir during atomic run

[dustymabe]

This commit has one simple goal which is to allow atomic run to
be executed against an installed directory just a little easier.

Before this commit we need:

atomic install myapp --destination=/path/to/local/dir
atomic run myapp --destination=/path/to/local/dir

After this commit:

atomic install myapp --destination=/path/to/local/dir
atomic run myapp /path/to/local/dir

[rtnpro]

More intuitive. LGTM 👍

[kadel]

why don't we allow same thing for install? eg. atomic install myapp /path/to/local/dir

[dustymabe]

/path/to/local/dir is a path to an "existing" application that has been extracted. In the case of install there is not yet an "existing" application, otherwise you wouldn't be calling install.

Does that make sense?

[cdrage]

LGTM 👍 and all tests pass!