test: add constants for PSBT key types (BIP 174)

Also take use of the constants in the signet miner to get rid of
magic numbers and increase readability and maintainability.

test/functional/test_framework/psbt.py

@@ -13,6 +13,57 @@ from .messages import (
 )
 
 
+# global types
+PSBT_GLOBAL_UNSIGNED_TX = 0x00
+PSBT_GLOBAL_XPUB = 0x01
+PSBT_GLOBAL_TX_VERSION = 0x02
+PSBT_GLOBAL_FALLBACK_LOCKTIME = 0x03
+PSBT_GLOBAL_INPUT_COUNT = 0x04
+PSBT_GLOBAL_OUTPUT_COUNT = 0x05
+PSBT_GLOBAL_TX_MODIFIABLE = 0x06
+PSBT_GLOBAL_VERSION = 0xfb
+PSBT_GLOBAL_PROPRIETARY = 0xfc
+
+# per-input types
+PSBT_IN_NON_WITNESS_UTXO = 0x00
+PSBT_IN_WITNESS_UTXO = 0x01
+PSBT_IN_PARTIAL_SIG = 0x02
+PSBT_IN_SIGHASH_TYPE = 0x03
+PSBT_IN_REDEEM_SCRIPT = 0x04
+PSBT_IN_WITNESS_SCRIPT = 0x05
+PSBT_IN_BIP32_DERIVATION = 0x06
+PSBT_IN_FINAL_SCRIPTSIG = 0x07
+PSBT_IN_FINAL_SCRIPTWITNESS = 0x08
+PSBT_IN_POR_COMMITMENT = 0x09
+PSBT_IN_RIPEMD160 = 0x0a
+PSBT_IN_SHA256 = 0x0b
+PSBT_IN_HASH160 = 0x0c
+PSBT_IN_HASH256 = 0x0d
+PSBT_IN_PREVIOUS_TXID = 0x0e
+PSBT_IN_OUTPUT_INDEX = 0x0f
+PSBT_IN_SEQUENCE = 0x10
+PSBT_IN_REQUIRED_TIME_LOCKTIME = 0x11
+PSBT_IN_REQUIRED_HEIGHT_LOCKTIME = 0x12
+PSBT_IN_TAP_KEY_SIG = 0x13
+PSBT_IN_TAP_SCRIPT_SIG = 0x14
+PSBT_IN_TAP_LEAF_SCRIPT = 0x15
+PSBT_IN_TAP_BIP32_DERIVATION = 0x16
+PSBT_IN_TAP_INTERNAL_KEY = 0x17
+PSBT_IN_TAP_MERKLE_ROOT = 0x18
+PSBT_IN_PROPRIETARY = 0xfc
+
+# per-output types
+PSBT_OUT_REDEEM_SCRIPT = 0x00
+PSBT_OUT_WITNESS_SCRIPT = 0x01
+PSBT_OUT_BIP32_DERIVATION = 0x02
+PSBT_OUT_AMOUNT = 0x03
+PSBT_OUT_SCRIPT = 0x04
+PSBT_OUT_TAP_INTERNAL_KEY = 0x05
+PSBT_OUT_TAP_TREE = 0x06
+PSBT_OUT_TAP_BIP32_DERIVATION = 0x07
+PSBT_OUT_PROPRIETARY = 0xfc
+
+
 class PSBTMap:
     """Class for serializing and deserializing PSBT maps"""