Replace the lightning symbol with Sats symbol for currency representation

[jurjendevries]

Currently, the lightning symbol is used in multiple places to represent an amount of sats (satoshis). However, the lightning symbol is specifically associated with the Bitcoin Lightning Network, and not with the currency itself. This can lead to confusion, as users might interpret the symbol as representing Liquid, eCash, or on-chain transactions instead of sats.

Proposed Solution: Replace the lightning symbol with the sats symbol https://satsymbol.com/ in all instances where it is used to represent the sats currency. The sats symbol is more accurate and unambiguous for this purpose.