Richer diff when running `cortextool diff|sync`

[gotjosh]

Right now, when you use the diff command it will only tell you which groups are going to be changed, but does not tell you which individual rules/alerts are changing.

I would be good to have an idea of what exactly is changing when you run this or the sync command.

[gotjosh]

To expand on this, it seems that running sync/diff after syncing will also result in updates - I would have expected this to no-op.

[justinTM]

@gotjosh take a look at this line: https://github.com/grafana/cortex-tools/blob/35691e0471880e9eb20562207976c5861df26455/pkg/rules/compare.go#L215

trying to figure out how to increase verbosity with a flag

[justinTM]

@gotjosh it is forced to false always: https://github.com/grafana/cortex-tools/blob/35691e0471880e9eb20562207976c5861df26455/pkg/commands/rules.go#L491

[justinTM]

@gotjosh see #199