Additional command for use in install.sh: ibek support add_runtime_folder

[gilesknap]

This function should do an idempotent add to a list of folders for copying into the runtime stage.

You can add folders to the runtime stage by explicitly putting them into the extract_runtime_assets function in Dockerfile. But it is much better if individual install.sh can control the list themselves.

This function would be very similar to add-dbds and add-libs but would add to the default list of things that extract_runtime_assets copies.

ALSO - extract_runtime_assets copies subfolders of each support module. The subfolder list is currently db/lib/bin - we need to add */protocol to that list in order to support streamdevices (to statically and dynamically linked modules)

@marcelldls this would be a nice issue for you to look at as you are getting into ibek's code

@amichelotti as discussed by email today.

[gilesknap]

PS I could not decide if this was an ioc or support namespace command. It is specifying a list for the ioc but it is a per support module thing and thus that is the correct namespace (analogous to ibek support add-dbds)

[gilesknap]

TODO: get this change in before release 3.0.0 (DONT FORGET */protocol)