refactor coordinates logging to use built in str formatting in logger

[Cadair]

Doing this should remove the need for if statements guarding the logging calls

[ayshih]

This is code in question:

sunpy/sunpy/coordinates/transformations.py

Lines 152 to 181 in 0f68569

	# Check if the logging level is at least DEBUG (for performance reasons)
	debug_output = log.getEffectiveLevel() <= logging.DEBUG
	if debug_output:
	# Indention for transformation layer
	indention = u"\u2502 " * _layer_level
	# For the input arguments, add indention to any lines after the first line
	from_str = str(args[0]).replace("\n", f"\n {indention}\u2502 ")
	to_str = str(args[1]).replace("\n", f"\n {indention}\u2502 ")
	# Log the description and the input arguments
	log.debug(f"{indention}{description}")
	log.debug(f"{indention}\u251c\u2500From: {from_str}")
	log.debug(f"{indention}\u251c\u2500To : {to_str}")
	# Increment the layer level to increase the indention for nested transformations
	_layer_level += 1
	result = func(*args, **kwargs)
	if debug_output:
	# Decrement the layer level
	_layer_level -= 1
	# For the output, add intention to any lines after the first line
	out_str = str(result).replace("\n", f"\n {indention} ")
	# Log the output
	log.debug(f"{indention}\u2514\u2500Out : {out_str}")

In principle, the log.debug() calls don't need the if debug_output: conditions, but we need to call log.debug() correctly such that it doesn't do any premature string formatting that will trigger __repr__() calls for the frame instances. This may be particularly tricky because I actually modify the __repr__() output:

sunpy/sunpy/coordinates/transformations.py

Lines 159 to 161 in 0f68569

	# For the input arguments, add indention to any lines after the first line
	from_str = str(args[0]).replace("\n", f"\n {indention}\u2502 ")
	to_str = str(args[1]).replace("\n", f"\n {indention}\u2502 ")

We should also benchmark before/after the refactor to make sure that the change isn't detrimental.