net-utils: clean up deprecated methods and update unit tests

[fkouteib]

Problem

Several methods in net-utils have been deprecated and replaced by methods in net-utils::sockets. However, the unit tests all still called the deprecated methods.

Summary of Changes

• Remove all deprecated code in net utils that's deprecated as of v2.3.2.
• Update unit tests to use the new net-utils::sockets methods adn structs.
• Fix test_bind() to adapt to re-use port flag no longer being set explicitly and directly in socket config.
• Retire test_multi_bind_in_range_with_config_reuseport_disabled() as it's no longer valid.

[fkouteib]

This test is no longer valid. We don't have direct/explicit control over setting/clearing re-use port flag. So multi-bind_*() always enables the re-use port and we can't test the combo desired in this test (multi-bind+re-use disabled).

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.3%. Comparing base (5f8b706) to head (d112fd4).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff            @@
##           master    #7508    +/-   ##
========================================
  Coverage    83.3%    83.3%            
========================================
  Files         810      810            
  Lines      364817   364639   -178     
========================================
- Hits       304147   304056    -91     
+ Misses      60670    60583    -87     

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[alexpyattaev]

Unfortunately the deprecation backport got stuck in review limbo so we can not actually axe these functions now #6705 . Since 3.0 is about to get cut it is probably worth changing these to deprecated in 3.0 and also kill that backport PR.