IOVDbFolder: Use AthMessaging and fix setting of message level

Inherit from AthMessaging and set our own message level to the one from IOVDbSvc. This fixes a problem introduced with https://gitlab.cern.ch/atlas/athenaprivate1/-/merge_requests/16127#note_3634697 where it was no longer possible to set the OutputLevel of messages originating from IOVDbFolder.

Also some general code cleanup and fix a few cppcheck warnings.

cc @sroe

This merge request affects 1 package:

• Database/IOVDbSvc

Adding @ssnyder as watcher

added Database master review-pending-level-1 labels

approved this merge request

CI Result SUCCESS (hash b5380892)

	Athena	AthSimulation	AnalysisBase	AthGeneration
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 17259]

Changes seem uncontroversial - approving.

Jon (L1)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 0afea2ef

added sweep:ignore label