[ANN] OrderPreservingDictionary version 1.5.0

After
  - BitmapCharacterSet [1]
  - XMLWriter [2]

were moved to "pharo-contributions" GitHub I also did a pass on OrderPreservingDictionary:

    https://github.com/pharo-contributions/OrderPreservingDictionary

which is now available as 1.5.0 version (and also as moving tag 1.5.x in case we provide
further hotfixes).

Basically cleanups were applied:
 - add missing comments
 - cleanup packaging
 - fixing typos
 - adding tools group for GT extensions
 - align CI definitions with projects like Seaside
 - CI green again (throwing out non-working Gemstone, volunteers welcomed)
 - fix catalog entry
 - deprecating http://smalltalkhub.com/#!/~PharoExtras/OrderPreservingDictionary and
   http://smalltalkhub.com/#!/~Pharo/OrderPreservingDictionary

You can load it using

  Metacello new
        baseline: 'OrderPreservingDictionary';
        repository: 'github://pharo-contributions/OrderPreservingDictionary/src';
        load

or via catalog in Pharo 7 and 8.

SIDE NOTE:
==========
As of today XMLWriter still requires the "OrderPreservingDictionary" project as a dependency.
OrderPreservingDictionary could be replaced by OrderedDictionary (same code, in the standard
image) - I will do a pass on that later on. For now I focus on moving the XML stuff to
GitHub first.


[1] https://lists.pharo.org/pipermail/pharo-users_lists.pharo.org/2019-October/044716.html
[2] https://lists.pharo.org/pipermail/pharo-users_lists.pharo.org/2019-October/044736.html