Pre-Release for new and stable APIs and n:m pub/sub communication

[dkroenke]

Hey folks,
as early christmas present we have a special gift for you: https://github.com/eclipse/iceoryx/releases/tag/v0.90.0

This is a pre-release for our first long-term-support release that is coming soon (will be iceoryx_1.0.0).

We had a major refactoring of the iceoryx communication infrastructure which allows to do n:m communication now and provides a flexible history functionality for late joining subscribers.

This new infrastructure is also made to support request/response communication as a next step (#27). The C++ API has been completely reworked and a new C API has been added.

We will give the API draft some weeks for finalizing the features and to incorporate feedback from the community. There's an issue in which we collect and discuss the final modifications (#408).

Major new features:

Complete refactoring of publishers and subscribers from shared memory data structures to user APIs, #252
First versions of new APIs for C++ and C, #252
n:m publish/subscribe communication now possible, #25
First version of a DDS gateway. Cyclone DDS already integrated, FastDDS on it's way, #64, #65
New GitHub actions for Mac OS and colcon build #175, #276. #328

If you have questions or remarks, just let a message here.

Have fun and merry Christmas!