Celix 2.2.0 release

[Pepijn Noltes <pe...@gmail.com>]

Hi All,

It is time - long overdue time - to start preparing for a new Celix release.

Although the current develop cycle has been quite long - more than a
year - I do think we made quite some progress with Celix considering
its small development team.
Just to highlight a few of the major improvements:

- Refactored the Celix build env to make use of depending/linking
against CMake targets.
- Clean up of the Celix project root dir.
- Made Celix bundles installable CMake targets.
- Added an alternative - more C oriented - celix_ prefixed api with -
IMO - a much more simpler to use API.
- Refactoring of Celix framework, registry and pubsub which fixes many
race condition issues!
- The dependency manager lib is now part of the Celix framework lib.
- Added avpr input support for lib dfi (dynamic function interface)

Also 3 new donations have been accepted:
 - HTTP Admin
 - TCP PubSubAdmin
 - Websocket PubSubAdmin

Before we can release a new Celix there are still some issues left, see [1].
If these issues are tackled I will start making a release branch and
following the Celix release procedure.
If there are any issues you like to be included in the 2.2.0 release,
please let us known.

Although I also really wanted to make some more steps concerning Celix
as a distribution package for the different distributions, I think we
still need to make some step concerning resolving of bundle paths.
I moved some of this work to the next release (2.3.0), see [2].

[1] https://issues.apache.org/jira/browse/CELIX/fixforversion/12342257
[2] https://issues.apache.org/jira/browse/CELIX/fixforversion/12342704


Greetings,
Pepijn