Set a default docker registry outside of profile scope.

The `docker.registry` configuration should always be set, as running
on cloud executors will need to pull docker images but will not
necessarily use the `docker` profile.

Author: robsyme

nextflow.config

@@ -168,7 +168,6 @@ profiles {
     }
     docker {
         docker.enabled         = true
-        docker.registry        = 'quay.io'
         docker.userEmulation   = true
         conda.enabled          = false
         singularity.enabled    = false
@@ -263,6 +262,9 @@ env {
     JULIA_DEPOT_PATH = "/usr/local/share/julia"
 }
 
+// Set default docker registry (will be unused unless pulling docker images)
+docker.registry = 'quay.io'
+
 def trace_timestamp = new java.util.Date().format( 'yyyy-MM-dd_HH-mm-ss')
 timeline {
     enabled = true