Allow SDA to show a receiving address even when it has no internet

[leto]

SDA should learn to cache locally one taddr and one zaddr so that people can show a QR to be paid, even with their internet turned off or without any internet access.

Currently, if SDA has no connection to SD or SDL, it's not possible to give someone an address to receive funds

So yes, SDA should learn to cache locally on taddr and one zaddr.

Here is what it would look like in BTC CLI,
[offline]$ hushd getnewaddress.
offline btc address
This would generate a new HUSH address.

Now you, or someone else, could fund this wallet with HUSH, and generate an offline tx to whomever, resulting in a QR code.
Then you would broadcast the tx on an online device, through a raw transaction.
And, to be on the safe side, do it through TOR. Because if you don't, you are at the mercy of the explorer that you broadcast the tx on.