Review home screen of the installer

[nondiremanuel]

I'm creating this issue to track the activity to be done to the home screen of the installer. The design is being finalized and will be linked to this issue, but the main idea is to have:

• Main options (Create / Add / Load) immediately visible at the landing page
• Network selection as a (secondary) option of this landing page. Bitcoin Network (mainnet) by default. TBD which network to load by default, if the last network I used with at least a wallet in it or always mainnet (I would go with the latter at least at first)
• Share Xpub option still present
• List of possible existing wallets to load for the specific network given the following limitations:
  • Still maximum one wallet for the ones that use their "own" BE (local bitcoind, local liana managed bitcoind, electrum)
  • Limit to be defined but more than one is possible for the ones with Liana Connect as BE
• The different wallets will be distinguished by some labels (e.g. "Liana Connect" vs "Bitcoin Core" vs "Electrum" or something like this) and will have more info if required (e.g. email address for "Liana Connect" wallets)

Below an example of the current draft design: