Improve instructions/ template

- replace walletconnect link with reown (rebranded): https://cloud.reown.com/app
- instead of access it on mobile through local hosting, it should explain how to di it through ngrok
- right now it's not flexible to deploy on another port than 3000. would be better if it would be dynamic, in case I have an app already running on 3000.
- update all mentioned of 'Frames' to 'MiniApp'
- instead of directing to the react README in the "[Deploy MiniApp section](https://github.com/celo-org/farcaster-template/blob/main/packages/docs/FRAME_DEVELOPMENT.md)", you should direct to the "Frame Deployment guide".
- in the frame deployment guide (rename to miniapp guide), you mention environment variables, that are not listed in the env.template file
- make sure to add Farcaster specific explanations/ features to template/ README: https://github.com/builders-garden/farcaster-miniapp-starter-celo