Investigate BTC testnet/regtest faucet functionality

[zone117x]

The new regtest-based testnet needs a BTC faucet. There is already code in the API that provides this:

stacks-blockchain-api/src/api/routes/faucets.ts

Lines 85 to 87 in 1a91639

	router.post(
	'/btc',
	asyncHandler(async (req, res) => {

Need to make sure it still works (hasn't been touched in years) and help devops with configuring it.

[smcclellan]

@CharlieC3 Is this going forward?

[CharlieC3]

@smcclellan There's a related devops issue with more context here:
https://github.com/hirosystems/devops/issues/1702

[zone117x]

Faucet is live. Any additional work to be tracked in the above devops issue