Create a pnpm script to generate MACI keys

[crisgarner]

As a dev, I would like to use a pnpm script to generate MACI keys to avoid to switch contexts and run node build/ts/index.js etc

[programmerraja]

Hey hai @crisgarner it's look intersting for me to work further on it can you explain more detail what excatly you excepting to do

[crisgarner]

if you see our MACI deployment guide (https://www.youtube.com/watch?v=-QA0VB9EUMk&t), we use most of the tasks as pnpm tasks, the idea is that instead of using the node build, etc.. we can just run pnpm genMaciKeys

[baumstern]

npx gen-maci-key would be also cool!

[programmerraja]

@crisgarner can you check my #1869 PR