Publish EBR builds of Orbit to N location by default

This leaves the latest-I available to redirect to new orbit-simrel
aggregated repo.

Part of eclipse-orbit/orbit-simrel#1

Jenkinsfile

@@ -8,7 +8,7 @@ pipeline {
     booleanParam(defaultValue: true, description: 'Whether the latest-X repository should reference this build, if it succeeds. Enabled by default. Generally this is disabled when building for a service release.', name: 'UPDATE_LATEST_X')
     string(defaultValue: 'main', description: 'The branch of the Git repositories that will be build. Committers should not need to touch this field.', name: 'BUILD_BRANCH')
     string(defaultValue: '', description: 'If a value is set, this will create a composite p2 repository pointing to this resulting build (if successful), at the given name under the downloads page.<br/><br/>This is only ever set to the release name (eg. 2019-06) for a milestone (S) build. The purpose is to give consumers a static location that tracks the release.', name: 'SIMREL_NAME')
-    choice(choices: ['I', 'S', 'M', 'R'], description: 'Valid options : I, S, M, or R. Most committers should be using I. S, M, or R should be done by a project lead, or someone tasked with putting together the release.', name: 'BUILD_LABEL')
+    choice(choices: ['N', 'S', 'M', 'R'], description: 'Valid options : N, S, M, or R. Most committers should be using N. S, M, or R should be done by a project lead, or someone tasked with putting together the release.<br/>Note that I should not be used anymore as that URL redirects to the new simrel-orbit infrastructure.', name: 'BUILD_LABEL')
     string(defaultValue: '', description: 'Description to appear on the downloads page.', name: 'DESCRIPTION')
   }
   agent {

releng/website/downloads/dlconfig.php

@@ -5,13 +5,13 @@
 $dropPrefix = array();
 $dropPrefix[]="R";
 $dropPrefix[]="S";
-$dropPrefix[]="I";
+$dropPrefix[]="N";
 $dropPrefix[]="M";
 
 $dropType = array();
 $dropType[]="<b>R</b>ecommended: Long term, persisted repositories.";
 $dropType[]="<b>S</b>table: To be used for Milestone builds";
-$dropType[]="<b>I</b>ntegration: Work towards next Stable (Milestone) build for SimRel";
+$dropType[]="<b>N</b>ightly: Consume by aggregator to produce simrel-orbit nightly build";
 $dropType[]="<b>M</b>aintenance: Work towards Oxygen.3a";
 
 // the "prefix" array and dropType array must be of same size, defined in right order