broken links to /compdemos/first_rhino/

[dtenenba]

URL of page(s) of concern
Specify the URLs of the page(s) where there are technical problems.

There are several broken links to /compdemos/first_rhino/. As far as I can tell using git log there was never any such page.
What should these links be changed to?

_hdc/workflows/running/run_script.md
119:([more details](/compdemos/first_rhino/#logging-on-to-gizmo-via-grabnode)).

_hdc/workflows/running_first_workflow.md
83:to keep a session open on [a grabbed node](/compdemos/first_rhino) for running

_scicomputing/compute_platforms.md
23:please see [this tutorial](/compdemos/first_rhino/)
31:More information on specific guidance for using `rhino` are in our Resource Library for [the basics](/compdemos/first_rhino/) and [for more detailed descriptions](/compdemos/howtoRhino/).

_compdemos/howtoRhino.md
79:"Grab" a node using one of the grab commands, you can read more about how to do this both [here](/compdemos/first_rhino/#logging-on-to-gizmo-via-grabnode) and [here.](/scicomputing/compute_platforms/#gizmo-cluster) Once done, the grab command you used will have created an ssh session to the remote node you have reserved, and you are now ready to run your app. Use the same commands as you would on a rhino (see above).