Refactor convert-dapp-pool and add CLI for Cross-App LP Token Swapping

[kmlbgn]

Description

Current logic for convert-dapp-pool is wrong and need to be refactored according to #675. There is no CLI to swap LP tokens either.

Expected Behaviour

• Refactor convert-dapp-pool. It should abstract 2 swaps from 2 RollApps pool.

• A CLI tool to facilitate the process of swapping LP tokens between different apps should also be added. The CLI should abstract and automate the following steps:

1. Redeem LP tokens from App1 (==obtaining Y dp and X kex from App1).
2. Sell Y dp from App1 for X kex using App1 pool.
3. Buy Z dp from App2 with X kex
4. Pool (deposit liquidity) X kex and Z dp from App2.
5. Obtain LP tokens from App2 from this deposit.