UI: Add main screen details

[thunderbiscuit]

Thanks for the PR!

I'd love to use GitHub for more explicit discussion of the PRs on iOS and what they bring into the codebase. Here are a few things we could start doing:

• Accompanying screenshots for the PRs showing the new screens/features (so that reviewers/designers who don't have access to simulators can see proposed changes)
• A few explanations as to the changes brought forward by the PR. New features, architectural decisions that were required, future development requirements related to the proposed changes

[geigerzaehler242]

This PR adds the following:

a wallet balance to the wallet screen with the ability to toggle between BTC and sats display. a sync button to cause the wallet to sync to the testnet a List of transactions with dummy data the send menu will now attempt a broadcast