* partial fix for #9836

This fixes that cleared error codes appear in DOOCS history where error
is not yet cleared.
It is only a partial fix since the history still contains more data than
was intended; intended was only first invalid data point

* remove comments about outdated concept

Co-authored-by: Dietrich Rothe <dietrich.rothe@desy.de>

Identical time stamps are considered to have identical data when DOOCS checks for inconsistencies on silent ZeroMQ connections. If on the same property new data is set without changing the VersionNumber, the timestamp will now be altered by 1 microsecond.

This is more like a temporary work around. A feature request to DOOCS should be made to introduce a distinction between a "server timestamp" and a "source timestamp" like it is realised in OPC UA.

Also a potential better solution to the other part of the problem inside ApplicationCore is described here: https://redmine.msktools.desy.de/issues/9723 

fix headers not being shown in QtCreator

Wip/bool and void

Consolidate coverage options

 - Remove Makefile.coverage.in
 - Drop BUILD_COVERAGE_ON_DEBUG for ENABLE_COVERAGE_REPORT (defaults to
    on if included)
 - Add clean-gcda target

this is required for dcmctrl7 config

This will be used unless overriden in doocs server conf

This fixes issues when using LaTeX in doxygen

This can potentially be a severe performance issue, if an application has many persisted large arrays.

Improvement8453 drothe large array persistency

- arrays are now by default saved just like spectra
- Short arrays go into main server config file, long into separate files
- only if array is writable
- behaviour is configurable in order to return to default behaviour of
DOOCS

- add new elements
- add persist element
- make definition less dependent on ordering in XML file
Now, all but one test xmls validate, and the one exception should
actually not do so.