[UI/UX] Alert against or prohibit the export/import of BSQ altcoin accounts

There are some misconceptions about the workings of the BSQ and its wallet inside Bisq and it can lead to the lost of funds. This is one of them. Prompted by this thread

When moving to a new directory or starting on an entirely different computer, Bisq allows you to export/import your National Currency and Altcoin accounts. And BSQ falls under Altcoin accounts. When using a new BTC wallet, importing the previous BSQ Altcoin account will cause you to send funds to an address of the previous wallet, that you may or may have not kept. Importing your BSQ account isn't an issue when you pretend to restore the previous BTC wallet but it should also be discouraged as it promotes address reuse.

Fortunately, there's no trade limits on Altcoin accounts based on Account age so there's nothing lost in discarding old BSQ Altcoin accounts.