[bug] WireGuard backend is missing parsers

[pandafy]

The WireGuard backend does not implement parsers.

netjsonconfig/netjsonconfig/backends/wireguard/parser.py

Lines 10 to 21 in 96d811f

	class WireguardParser(BaseParser):
	def parse_text(self, config):
	raise NotImplementedError()
	def parse_tar(self, tar):
	raise NotImplementedError()
	def _get_vpns(self, text):
	raise NotImplementedError()
	def _get_config(self, contents):
	raise NotImplementedError()

We need to add parsers like OpenVPN backend.