repo rework: Remove need for repos to be self-aware

* See #12917 for details.
* Squashed to one commit to make revert easy if we
  run into any issues.
* pkgman is now pre-attached to the 'current' repo
  version within nightly images so they can be updated
  by default.
* This shouldn't impact us keeping older sets of package
  versions by commit hash for building older hrevs.
* There are XXX stubs with "Kill me". These will need
  to be dropped after users are given sufficent time to
  upgrade. We're dropping a previously required field (url)
  so making this a slowish roll out.
* Makes the repos a lot less restrictive which should
  help PM package building automation be a bit easier.
* Once this stuff smooths out, we'll add UUID's to the
  repo definitions for duplicate repo detection.

build/jam/repositories/Haiku

@@ -52,4 +52,8 @@ if $(webPositiveIsAvailable) {
 	packages += webpositive ;
 }
 
-HaikuRepository $(haikuRepository) : $(repoInfo) : $(packages:S=.hpkg) ;
+local version = current ;
+#local version = $(HAIKU_VERSION) ;
+local remoteURL = http://packages.haiku-os.org/haiku/master/$(HAIKU_PACKAGING_ARCH)/$(version) ;
+
+HaikuRepository $(haikuRepository) : $(repoInfo) : $(packages:S=.hpkg) : $(remoteURL) ;