[feature]: define URI scheme for taproot asset on chain payments

[ZZiigguurraatt]

We have an on chain taproot payment address format defined (https://github.com/Roasbeef/bips/blob/bip-tap/bip-tap-addr.mediawiki), but there is no URI scheme like BIP 21 (https://github.com/bitcoin/bips/blob/master/bip-0021.mediawiki) or or BIP 321 (bitcoin/bips#1555).

Need to define a URI scheme and mime type for using with wallets since on chain payments don't use standard lightning invoices like off chain payments do.