Reordering stuff to alphabetical order + SYN Cookies

[joubbi]

Everything seems to be in random order, which makes it harder to read. I moved things around and might continue doing that if I feel like having the time doing that while I try to figure out what this role actually does.

SYN cookies is not enabled. I think it should.

CIS Benchmark:

3.2.8 Ensure TCP SYN Cookies is enabled (Scored)
Profile Applicability:
 Level 1 - Server
 Level 1 - Workstation
Description:
When tcp_syncookies is set, the kernel will handle TCP SYN packets normally until the
half-open connection queue is full, at which time, the SYN cookie functionality kicks in. SYN
cookies work by not using the SYN queue at all. Instead, the kernel simply replies to the
SYN with a SYN|ACK, but will include a specially crafted TCP sequence number that
encodes the source and destination IP address and port number and the time the packet
was sent. A legitimate connection would send the ACK packet of the three way handshake
with the specially crafted sequence number. This allows the system to verify that it has
received a valid response to a SYN cookie and allow the connection, even though there is no
corresponding SYN in the queue.
Rationale:
Attackers use SYN flood attacks to perform a denial of service attacked on a system by
sending many SYN packets without completing the three way handshake. This will quickly
use up slots in the kernel's half-open connection queue and prevent legitimate connections
from succeeding. SYN cookies allow the system to keep accepting valid connections, even if
under a denial of service attack.
Audit:
Run the following commands and verify output matches:
sysctl net.ipv4.tcp_syncookies
net.ipv4.tcp_syncookies = 1
grep "net.ipv4.tcp_syncookies" /etc/sysctl.conf /etc/sysctl.d/*
net.ipv4.tcp_syncookies = 1

[rndmh3ro]

I like that.

As for the syncookie change: Can you please do that in another PR to not mix these issues? Also you have to remove it here then: https://github.com/dev-sec/ansible-collection-hardening/blob/master/roles/os_hardening/vars/Amazon.yml#L44