Support P4.org In-band Network Telemetry (INT)

[jingfeihu]

Brief description

I would like to contribute P4.org In-band Network Telemetry (INT) protocol to scapy.
Partly of the INT layer has been implemented.
I hope everyone who are interested in this can join us to enhance it.

References:
https://staging.p4.org/p4-spec/docs/INT_v2_1.pdf
https://staging.p4.org/p4-spec/docs/telemetry_report_v2_0.pdf
https://github.com/p4lang/p4-applications

Example Packet Formate:
INT-MX mode:
INToGre = Ether/IP/GRE/INTShimGre/INTMetaMx/Raw
INToTCP = Ether/IP/TCP/INTShimTcpUdp/INTMetaMx/Raw
INToUDP = Ether/IP/UDP/INTShimTcpUdp/INTMetaMx/Raw
INToVXLAN = Ether/IP/UDP/VXLAN/INTShimVxlan/INTMetaMx/Raw
INToGENEVE = Ether/IP/UDP/GENEVE/GeneveOptINT/INTMetaMx/Raw
INT-MD mode:
INToGre = Ether/IP/GRE/INTShimGre/INTMetaMd/INTMetaHop/Raw
INToTCP = Ether/IP/TCP/INTShimTcpUdp/INTMetaMd/INTMetaHop/Raw
INToUDP = Ether/IP/UDP/INTShimTcpUdp/INTMetaMd/INTMetaHop/Raw
INToVXLAN = Ether/IP/UDP/VXLAN/INTShimVxlan/INTMetaMd/INTMetaHop/Raw
INToGENEVE = Ether/IP/UDP/GENEVE/GeneveOptINT/INTMetaMd/INTMetaHop/Raw

Scapy version

2.5.0

Python version

3.7

Operating system

Linux 5.10.27-051027-generic

Additional environment information

No response

How to reproduce

ignore

Actual result

No response

Expected result

No response

Related resources

No response

[jingfeihu]

This is the PR:
#4230