Add button "Receive via Keysend"

[Darth-Coin]

Describe your enhancement idea

We need to have a quick access to the keysend feature not only for sending but also for receiving.
I suggest to add a simple button in the receive screen.
Keysend is a powerful feature for LN that is really underrated.

Also some important aspect: add route hints into this keysend QR generated for the embedded nodes.
This way any Zeus node mobile user could send each others sats easily through keysend.
Like Blixt does:

"[{\"hopHints\":[{\"nodeId\":\"0230a5bca558e6741460c13dd34e636da28e52afd91cf93db87ed1b0392a7466eb\",\"chanId\":\"17592186044416001076\",\"feeBaseMsat\":0,\"feeProportionalMillionths\":300,\"cltvExpiryDelta\":40}]},{\"hopHints\":[{\"nodeId\":\"028c589131fae8c7e2103326542d568373019b50a9eb376a139a330c8545efb79a\",\"chanId\":\"17592186044416000010\",\"feeBaseMsat\":1000,\"feeProportionalMillionths\":1,\"cltvExpiryDelta\":40}]}]"

[kaloudis]

Sending to keysend w routing hints, via Blixt https://github.com/hsjoberg/blixt-wallet/blob/5336c28f0ac71ea994def0d6ea712778c936f129/src/lndmobile/index.ts#L347

[kaloudis]

I also think if we add it, the QR should be on a different receive view as the current one is already very cluttered. maybe there could be a Keysend Receive option under the lightning balance slider