Witness size worst case calculation

[darosior]

We have this calculation for the number of executed OPs and the number of stack elements. It would be nice to implement it for the witness size as well, as it would allow to compute feerate of presigned transactions in advance.

[darosior]

The relevant data structure where we track those:

python-bip380/bip380/miniscript/satisfaction.py

Lines 189 to 206 in 7b79c47

	class ExecutionInfo:
	"""Information about the execution of a Miniscript."""
	def __init__(self, stat_ops, _dyn_ops, sat_size, dissat_size):
	# The *maximum* number of *always* executed non-PUSH Script OPs to satisfy this
	# Miniscript fragment non-malleably.
	self._static_ops_count = stat_ops
	# The maximum possible number of counted-as-executed-by-interpreter OPs if this
	# fragment is executed.
	# It is only >0 for an executed multi() branch. That is, for a CHECKMULTISIG that
	# is not part of an unexecuted branch of an IF .. ENDIF.
	self._dyn_ops_count = _dyn_ops
	# The *maximum* number of stack elements to satisfy this Miniscript fragment
	# non-malleably.
	self.sat_elems = sat_size
	# The *maximum* number of stack elements to dissatisfy this Miniscript fragment
	# non-malleably.
	self.dissat_elems = dissat_size