ci: add AvailabilitySet + SLB E2E scenario

[jackfrancis]

Reason for Change:

This PR adds an E2E cluster configuration scenario for AvailabilitySet (i.e., not VMSS) and Standard Load Balancer.

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[codecov]

Codecov Report

Merging #2578 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2578   +/-   ##
=======================================
  Coverage   72.15%   72.15%           
=======================================
  Files         130      130           
  Lines       24486    24486           
=======================================
  Hits        17668    17668           
  Misses       5797     5797           
  Partials     1021     1021

[jackfrancis]

Out of band jenkins validation passed

[devigned]

/lgtm

[acs-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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