Run clang-tidy modernize-use-override to remove all the redundant
virtual keywords from overridden methods, and add some missing
overrides.
Another benefit is that this has also added the overrides
on destructors, which will cause a build failure if a base
class is missing a virtual destructor.
- Add server exception base class
- Enable per service exception definition
- Handle QgsException gracefully (error 500)
- Handle OGC exception versioning
