Allow conventions to react to sequence operations

[roji]

In EFCore.NamingConventions, there's a request to rewrite the naming of sequences when they're added by convention, e.g. by TPC (issue). However, it seems that there's currently no way to do that (no ISequenceAddedConvention, and IModelAnnotationChangedConvention does not get fired when a sequence gets added).

/cc @AndriySvyryd

[AndriySvyryd]

Requires #19806