Be explicit if not reference file comparison is used by unit test.

DataQualityInterfaces, LArGeoEndcap, DumpEventDataToJSON, BeamPipeGeoModel cppcheck / clang-tidy fixes

(don't create configuration classes at module level)

Updated AtlasGeometryCommon packages to use FindGeoModel.cmake. Which was introduced
to serve the new GeoModel uni-project, which was introduced into our build with !39900.

Bonus:
 * Turned CavernInfraGeoModel into component-only package
 * Removed several commented-out include statements from VP1DetInfo.cxx

If a dtor is final, the class itself should also be final.

Enable thread-safety checking.

Dropped the redundant AbsMaterialManager interface, and removed all references to this
interface from client packages.

Dropped redundant methods from RDBMaterialManager, and in this way got rid of lots of
duplicated code.

- remove `atlas_depends_on_subdirs`
- update link dependencies
- replace `atlas_install_headers` with interface library or remove it
  entirely if headers not used outside package
- enable flake8 where applicable

There is already a library that provides the public headers and hence
the `atlas_install_headers` is redundant.

If a dtor is declared final, the class itself should also be declared final.

If a dtor is declared final, the class itself should also be declared final.

Library dependency fixes.

Library dependency fixes.

This package has a component library, but it also exports headers.
Define an interface library for the headers.

Library dependency fixes.

StatusCodeSvc is deprecated. Remove all references to it from job
options.

In the "new packaging" the external is now called like that...

Updated `ComponentAccumulator` configuration tests which dump the configuration to a pickle file.
In python 3 the output file needs to be explicitly opened in binary mode.
I.e.
```
f = open('configdump.pkl', 'wb')
```
rather than
```
f = open('configdump.pkl', 'w')
```

Fix warnings/errors flagged by `flake8`. Mostly unused variables/imports
or stylistic code problems.