Add access control to varnish

[AbdelrahmanElawady]

Add access control to Varnish server with the same rules as TS.

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Which Traffic Control components are affected by this PR?

• Traffic Control Cache Config (t3c, formerly ORT)

What is the best way to verify this PR?

following the same steps in #7669

• if Varnish is running as edge, try adding -X "PURGE" to curl command and it should return not allowed.
• if Varnish is running as mid, same thing as edge but change the domain to mid-01.infra.ciab.test. it will return not allowed too.
• you can also check VCL output at /opt/cache/etc/varnish/default.vcl

PR submission checklist

• This PR has tests
• This PR has documentation
• This PR has a CHANGELOG.md entry
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

Fixes: #7714

[AbdelrahmanElawady]

marked as draft until #7669 is merged

[codecov]

Codecov Report

Merging #7700 (ec64608) into master (fe12a38) will increase coverage by 2.49%.
Report is 20 commits behind head on master.
The diff coverage is 74.12%.

@@             Coverage Diff              @@
##             master    #7700      +/-   ##
============================================
+ Coverage     26.88%   29.38%   +2.49%     
  Complexity       98       98              
============================================
  Files           691      594      -97     
  Lines         81154    74530    -6624     
  Branches         90       90              
============================================
+ Hits          21817    21897      +80     
+ Misses        57261    50550    -6711     
- Partials       2076     2083       +7     

Flag	Coverage Δ
golib_unit	53.13% <74.12%> (+5.12%)	⬆️
grove_unit	12.02% <ø> (+7.41%)	⬆️
t3c_unit	5.99% <ø> (+1.08%)	⬆️
traffic_monitor_unit	26.22% <ø> (+4.92%)	⬆️
traffic_ops_unit	22.38% <ø> (+0.22%)	⬆️
traffic_stats_unit	10.76% <ø> (+0.62%)	⬆️
unit_tests	26.13% <74.12%> (+2.52%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
lib/varnishcfg/backends.go	71.07% <ø> (-2.01%)	⬇️
lib/varnishcfg/vcl.go	17.39% <0.00%> (+17.39%)	⬆️
lib/varnishcfg/vclbuilder.go	10.52% <0.00%> (+10.52%)	⬆️
lib/go-atscfg/ipallowdotyaml.go	74.53% <65.97%> (+2.91%)	⬆️
lib/varnishcfg/access_control.go	96.10% <96.10%> (ø)

... and 106 files with indirect coverage changes

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[zrhoffman]

Looks good, thanks!