Add a binary file for setting up firewall rules on the VM

[larohra]

Description

This is the 1st PR for the change to add firewall rules to the VM on system reboot (since iptables are not persisted on reboots).

This PR deals with -

• Creating a new binary file for the sole purpose of setting up waagent-network rules
• Separating out the bare minimum needed for setting up the firewall rules

Issue #

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PR information

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Quality of Code and Contribution Guidelines

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[larohra]

These 2 commands are all we need to setup the rules on system reboot so just created a new Util just for them

[codecov]

Codecov Report

Merging #2147 (9cb1668) into develop (f0f326b) will increase coverage by 0.06%.
The diff coverage is 78.57%.

@@             Coverage Diff             @@
##           develop    #2147      +/-   ##
===========================================
+ Coverage    70.64%   70.71%   +0.06%     
===========================================
  Files           95       95              
  Lines        12939    12965      +26     
  Branches      1842     1844       +2     
===========================================
+ Hits          9141     9168      +27     
  Misses        3390     3390              
+ Partials       408      407       -1     

Impacted Files	Coverage Δ
azurelinuxagent/agent.py	48.95% <ø> (ø)
azurelinuxagent/common/osutil/default.py	59.86% <57.14%> (+0.15%)	⬆️
azurelinuxagent/common/utils/networkutil.py	89.65% <82.85%> (-4.58%)	⬇️
azurelinuxagent/ga/collect_telemetry_events.py	90.34% <0.00%> (+0.68%)	⬆️

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[larohra]

The idea is to create a new service file which would call this binary to setup the network rules on startup. Adding another parameter to our /sbin/waagent binary was being a bit painful because that way we would've needed to separate out all dependencies on the VM (like file access, network access, etc) because we plan to run this service way high up in the boot order where these bare minimum dependencies would not be available.

Setting up the new service would come in subsequent PRs