Embeddedjs zos library symbol resolution support

[1000TurquoisePogs]

It would be convenient for certain properties of zowe.yaml to contain symbols that are resolved.
Imagine you want to state the hostname of something.
If we had

zowe:
  externalDomains:
    - ${{ zoslib.getSymbol('&hostname') }}

I think that would be great.
It looks like the call that is needed for symbol resolution is https://www.ibm.com/docs/en/zos/2.5.0?topic=hsp-asasymbm-asasymbf-substitute-text-symbols so it would be a good addition to the codebase and would be reused for other things (dataset api needs symbol resolution on volser)

[1000TurquoisePogs]

This code was just merged to configmgr, so hopefully the capability will be in 2.9.
at that point, it'll just be a matter of leveraging it in the yamls.
the function is zos.resolveSymbol('&thing')