cylc: also look for apps in share/app

[oliver-sanders]

When run in by a Cylc workflow, rose task-run looks for apps in a Rose suite configuration's app/ directory.

To assist the dynamic installation of applications, we should consider also looking in the share/app directory. This would compliment Cylc's addition of share/bin into the $PATH in the job execution environment.

One question, if we did this, what would be the search order?

• app/
• share/app

Or the other way around?

Or should duplicate applications cause errors?