Registering as Drep should include mandatory or optional re-delegation to yourself.

## Context & versions
staging.sanchonet

## Check out the Loom: https://www.loom.com/share/5483fb90059b4c5e9a1751f578309cdf?sid=b7901242-5de4-4e56-abfe-7ff2ec1bb639

## Steps to reproduce

1. Delegate your voting power to Abstain
2. Become a DRep

## Actual behavior
You are a drep, but your voting power is still delegated to Abstain

## Expected behavior
It would be nice if there was a 'delegate all my ADA-power' to myself option in the 'become a Drep flow'. Otherwise, the situation is quite awkward, and the user then presumably will have to manually delegate their Voting Power to themselves in a separate, second step.

## What to do?
Design an optional or mandatory re-delegation into the DRep registration flow.