Regroup headers instead of preserving them

[armallen]

Using Preserve, this header list:

#include <memory>

#include <orion_engine/integrity_preprocessor/read_yaml_configuration.h>
#include <orion_engine/orion/create_integrity_preprocessor.h>

#include <orion_engine/integrity_common/read_antex_file.h>
#include <orion_engine/integrity_preprocessor/create_integrity_preprocessor_from_config.h>
#include <public_types/logging.h>

#include <string>
#include <utility>

is valid and won't be reformatted.

Using Regroup, the list is reformatted to:

#include <orion_engine/integrity_common/read_antex_file.h>
#include <orion_engine/integrity_preprocessor/create_integrity_preprocessor_from_config.h>
#include <orion_engine/integrity_preprocessor/read_yaml_configuration.h>
#include <orion_engine/orion/create_integrity_preprocessor.h>
#include <public_types/logging.h>

#include <memory>
#include <string>
#include <utility>

[sbmueller]

Not a change request for this PR, but I think we still need to

1. Publicly announce the change and ask for opinions
2. Update the guidelines with the new behavior

[sbmueller]

Question: Which formatter did you use for this file?

[armallen]

It should be redhat.vscode-yaml VSCode extension https://marketplace.visualstudio.com/items?itemName=redhat.vscode-yaml