Disabled resources should not be listed in search drop-down

[glopesdev]

The ResourceNameConverter helper class provides functionality for listing in a drop-down the available resources declared by a workflow for nodes needing to reference specific resource names. The class makes a scope-dependent search through workflow nodes and returns all resource strings in specific resources.

Unfortunately it will currently return strings even for resources provided by disabled nodes. Filtering out these resources would reduce the likelihood of errors and also enable fallback dropdowns in cases where no resource is found (e.g. serial port names).