Make DOH more friendly to other AMD loaders:
    - specify baseUrl explicitly
    - specify mapping from doh --> util/doh explicitly
    - don't depend on mapping from doh to doh/main
    Make DOH more friendly to other AMD loaders (continuation):
    use tlmSiblingOfDojo etc. to make things still work with dojo V1 loader

    Refs #16585
Merge remote-tracking branch 'upstream/master' into custom3