debugindex: introduce a concept of "verbose-only" column We are about to add a bunch of new column and most of them are probably only relevant to --verbose. We add some more testing of the `--verbose` mode in a sidedata context.

debugindex: move to a flexible column Each column is now declared as a decorated function. This will make it much simpler to add more new column in the future.

debugindex: rename the parent column to mention nodeid We will add new columns with the "revnum" version of the parent. It will be useful in case we need to inspect a corrupted revlog index.

debugindex: align column name on the right It will be simpler to align everything on the same side, and the right seems a better side as it match the value alignment.