This reverts merge request !524

The StatusCode now consists of a value and category/domain. By default
StatusCodes are created within a "default category". But users can
define new categories and StatusCodes using typed enums. The design is
mainly borrowed from std::error_code.

Main changes:
- StatusCode::setCode has been removed
- No implicit conversions from/to bool or int anymore. This greatly
  increases type safety.
- Converted all unscoped enums in Gaudi to their own StatusCode
  category (Clients will have to adjust their code to the scoped enum
  names (e.g. ERR -> Status::ERR)
- Added operator bool() that is equivalent to isSuccess()
- Added ternary (bitwise) AND(&) and OR(|) operators to combine
  StatusCodes according to three-valued logic
- Added extensive unit tests for all StatusCode features

Impact on clients:
- Code that relies on the implicit StatusCode<->bool/int conversion has
  to be changed to explicitly construct/convert StatusCodes via either
  the constructor, operator bool() or getCode().
- Clients using Gaudi StatusCodes need to adjust to using the scoped
  enums. E.g. clients of the ConversionSvc need to change BAD_STORAGE_TYPE to
  Status::BAD_STORAGE_TYPE when checking for specific StatusCode return
  types.

- and some minor format tweaking

- remove destructors qualified with 'override = default'
- prefer inheriting constructors

... plus some formatting tweaks,

- replace union with boost::variant
- replace call_ template with simpler fwd template
- add compose to compose lambdas

This allows/forces DataSvc and TsDataSvc to avoid temporary std::string
objects.

preserve thread safety and fix the regression reported in GAUDI-1319

Refactor the HistogramSvc to be suitable as a base class. Several Histogram and Profile utility classes also become public.

Moved HistogramPersistencySvc.h/cpp into its own subdirectory. To avoid mixing globbing expressions in the configuration with simply listing source file names.

Adding changes that make it possible to build Gaudi without AIDA and CppUnit. With a reduced set of compiled code of course.

in those classes the override is needed or not depending on the teplpate
parameter, so the only solution is to hide the warning.

flagged those include directories as "-system".

also applied clang-format to all modified files

also applied clang-format to all modified files