Remove dsinternals dependency

[anadrianmanrique]

This PR removes dependency with dsinternals library, used in the context of shadow credentials in ntlmrelayx.
fixes #1637

[gabrielg5]

Hey!

From a functional point of view working fine with changes implemented (working like the current master version)

Only one detail, related to the new added helper file impacket/examples/ntlmrelayx/attacks/shadow_credentials.py
If running ntlmrelayx with debug flag enabled, it shows an error that an attribute in that attack is not present

[+] module 'impacket.examples.ntlmrelayx.attacks.shadow_credentials' has no attribute 'PROTOCOL_ATTACK_CLASS'

They are automatically loaded at

impacket/impacket/examples/ntlmrelayx/attacks/__init__.py

Lines 46 to 77 in 985690e

	for file in pkg_resources.resource_listdir('impacket.examples.ntlmrelayx', 'attacks'):
	if file.find('__') >= 0 or file.endswith('.py') is False:
	continue
	# This seems to be None in some case (py3 only)
	# __spec__ is py3 only though, but I haven't seen this being None on py2
	# so it should cover all cases.
	try:
	package = __spec__.name # Python 3
	except NameError:
	package = __package__ # Python 2
	__import__(package + '.' + os.path.splitext(file)[0])
	module = sys.modules[package + '.' + os.path.splitext(file)[0]]
	try:
	pluginClasses = set()
	try:
	if hasattr(module, 'PROTOCOL_ATTACK_CLASSES'):
	# Multiple classes
	for pluginClass in module.PROTOCOL_ATTACK_CLASSES:
	pluginClasses.add(getattr(module, pluginClass))
	else:
	# Single class
	pluginClasses.add(getattr(module, getattr(module, 'PROTOCOL_ATTACK_CLASS')))
	except Exception as e:
	LOG.debug(e)
	pass
	for pluginClass in pluginClasses:
	for pluginName in pluginClass.PLUGIN_NAMES:
	LOG.debug('Protocol Attack %s loaded..' % pluginName)
	PROTOCOL_ATTACKS[pluginName] = pluginClass
	except Exception as e:
	LOG.debug(str(e))

Perhaps moving that class to another folder (ie: impacket/examples/ntlmrelayx/utils)?

I'm still checking the code, later today will update 🚀