Prompt user before going backwards to catchpoint

## Problem

If a user runs conduit with the `-r` flag to specify a specific start round, then exits the process, then reruns the same command, conduit will immediately set the follower node back to the most recent catchpoint and restart the entire catchup process, which is very time consuming.

## Solution

Have conduit prompt the user if they want to revert to the given round. Probably good to have a flag to automatically answer yes for non-interactive environments.

## Dependencies

None, should be minimal effort. I can take a crack at it this week but don't have a ton of Go experience.

## Urgency

Medium? Definitely would cause for less head-to-desk moments when developing/deploying conduit.