Parse `info`, `source`, `destination`, etc. when using ek mode

[miaotony]

Is your feature request related to a problem? Please describe.
I would like to get both detailed decoding info (including raw packet) and summary info (like one row in wireshark GUI), however from what I have tried in JSON / PDML / PSML mode tshark cannot provide both info. (If I'm not mistaken...

After trying EK mode with parameters -P -V -x, I surprisingly find that it provides what I want.

Describe the solution you'd like
When using EK mode, provide some interfaces/functions or a dict containing the other fields besides layers.

Describe alternatives you've considered
When parsing raw json_pkt, the code only pick layers for further parsing and the other fields are ignored.

pyshark/src/pyshark/tshark/output_parser/tshark_ek.py

Lines 37 to 58 in 803d76c

	def packet_from_ek_packet(json_pkt):
	if USE_UJSON:
	pkt_dict = ujson.loads(json_pkt)
	else:
	pkt_dict = json.loads(json_pkt.decode('utf-8'))
	# We use the frame dict here and not the object access because it's faster.
	frame_dict = pkt_dict['layers'].pop('frame')
	layers = []
	for layer in frame_dict['frame_frame_protocols'].split(':'):
	layer_dict = pkt_dict['layers'].pop(layer, None)
	if layer_dict is not None:
	layers.append(EkLayer(layer, layer_dict))
	# Add all leftovers
	for name, layer in pkt_dict['layers'].items():
	layers.append(EkLayer(name, layer))
	return Packet(layers=layers, frame_info=EkLayer('frame', frame_dict),
	number=int(frame_dict.get('frame_frame_number', 0)),
	length=int(frame_dict['frame_frame_len']),
	sniff_time=frame_dict['frame_frame_time_epoch'],
	interface_captured=frame_dict.get('rame_frame_interface_id'))

Maybe you can add a dict in Packet class and set its default value to None to include the other fields meanwhile keeping compatibility.

BTW, you have to pay attention to pass -P -V parameters to tshark, just like LiveRingCapture in #573 .

Thank you very much!