[Draft] Remove Work-Arounds for ADIOS2<2.7.0

Author: ax3l

docs/source/backends/adios2.rst

@@ -22,6 +22,7 @@ Steps
 
 ADIOS2 is optimized towards organizing the process of reading/writing data into IO steps.
 In order to activate steps, it is imperative to use the :ref:`Streaming API <usage-streaming>` (which can be used for either file-based or streaming-based workflows).
+@franzpoeschel: let's remove these work-arounds :-)
 With ADIOS2 release 2.6.0 containing a bug (fixed in development versions, see `PR #2348 <https://github.com/ornladios/ADIOS2/pull/2348>`_) that disallows random-accessing steps in file-based engines, step-based processing must currently be opted in to via use of the :ref:`JSON parameter<backendconfig>` ``adios2.engine.usesteps = true`` when using a file-based engine such as BP3 or BP4.
 With these ADIOS2 releases, files written in such a way may only be read using the streaming API.
 Upon reading a file, the ADIOS2 backend will automatically recognize whether it has been written with or without steps, ignoring the JSON option mentioned above.

include/openPMD/IO/ADIOS/ADIOS2IOHandler.hpp

@@ -1245,6 +1245,8 @@ namespace detail
              *    is opt-in for now.
              * 2) Reading with the Streaming API any file that has been written
              *    without steps.
+             *
+             * @todo [franzpoeschel] let's remove these work-arounds :-)
              */
             NoStream,
             /**
@@ -1260,6 +1262,8 @@ namespace detail
              * and attributes in the file will be shown.
              * Hence, streamStatus == Parsing means that the first step has yet
              * to be opened.
+             *
+             * @todo [franzpoeschel] let's remove these work-arounds :-)
              */
             Parsing,
             /**