Add Watch-Only Addresses to Ledger Live

[KarmCraft]

I wish to add watch-only addresses to the Ledger Live Desktop App. These are addresses that have not been generated with a Ledger device but are just taken from the public blockchain.

These addresses would also contribute to the statistics of the portfolio. Ideally the portfolio balance can be shown with and without the watch-only addresses.

To avoid spamming too many watch-only addresses and overloading of the background API calls a limit on how many watch-only addresses can be added, for instance 50 per installation.