#23783 Symlink support in folder creation

Adds support for symbolic links in the folder creation system. Currently non-windows only but easily modifiable through hook extension to support windows if this is desirable.

Create a file named `foo_bar.symlink.yml` in the folder schema and a `foo_bar` symlink will appear as
folders are created. The `foo_bar.symlink.yml` needs to have a target key, which can refer to dynamic entries higher up the current path, for example

```
target: ../$Shot/$Project/hello
```