Add initial support for multiple compute backends. Closes #1186, #1226 (

#1227)

* WIP #1186 rough refactor of the job execution backend

* WIP #1186 added more support for local execution

* WIP extra comments and tmp workarounds

* WIP added symlink to node_modules in local worker

* WIP fixed file collection

* WIP #1186 updated local executor to upload results

* WIP #1186 removed stderr (debug) output

* WIP Added notes for next steps and stdout logging

* WIP #1186 upload, job queueing for local executor

* WIP #1186 adding cancel support

* WIP #1186 changed from polling to events

* WIP Update stop execution to communicate with backend

* WIP rename silentStopExecution

* WIP #1186 convert dict values to nodes so it will be updated on save

* Update cached nodes on SYNCED. Fixes #1226

* WIP #1186 expose execution backend as component setting

* WIP #1186 Fixed indentation

* WIP rename "View workers" -> "View compute"

* WIP #1186 Moved backend whitelisting to execution

* WIP minor cleanup

* WIP #1186 Refactored backends for client and status info

* WIP #1186 refactored JobResults

* WIP Updated 'update' event to accept jobId (not jobInfo)

* WIP #1186 update gme compute backend compute

* WIP #1186 misc code clean

* WIP #1186 ensure compute backends can be loaded synchronously

* WIP Created basic ComputeDialog for compute dashboards

* WIP pass logger to dashboards

* WIP #1186 Added gme dashboard

* WIP Fixed gme compute dashboad

* WIP Add tabs and support for multiple backends

* WIP Add msg when no compute backends

* WIP renamed execution->compute

* WIP (more) rename execution-compute

* WIP Changed from index.js to metadata.json files

* WIP updated dashboard to use actual name

* WIP renamed ExecutionEnv->ExecutorHelper

* WIP #1186 delete executionId attribute on completion

* Ensure gme backend is used by default (don't change default behavior)

* WIP fixed bug in ExecuteJob

* WIP update terminology

* WIP Fixed linting issues

* WIP Updated tests

* WIP removed unreachable code

* WIP fixed failing test

config/components.json

@@ -129,5 +129,8 @@
                 "description": "Artifacts from pipeline executions are stored here."
             }
         ]
+    },
+    "Compute": {
+        "backends": ["gme", "local"]
     }
 }