Add support for generating aliases for immediate children directories (i.e. child directories one level below the parent) inside a given directory.

[Wembley Leach]

e.g., given this directory layout:

some
└── random
    └── path
        ├── one
        ├── three
        └── two

and this configuration:

[*]/some/random/path

The aliases alias one='cd /some/random/path/one', alias two='cd /some/random/path/two', and alias three='cd /some/random/path/three' should be created.