Make inputs symlink in control directory

[aidanheerdegen]

Just an example of using the new support for symlinks in this payu PR

payu-org/payu#518

I don't think it should be merged as-is, but wanted it available for others to see how it might work.

It has a couple of nice advantages:

1. Reduces the amount of path verbiage in config.yaml
2. Makes the configuration more relocatable. Just a single symlink need be changed if the location of the inputs were moved (or we were using a different HPC platform?)

Note: I could have made the link into the access-om2 directory directly, but this would not have included the JRA55 forcing data in inputs/JRA-55/RYF/v1-4/data.

Note also: the bin hashes of the input files changed because they're now resolving the symlink from the old location in experiments.