Create Load Balancer cmdlets with generated code

[khannarhea]

Description

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate change log has been updated
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • the changes have gone through a cmdlet design review
  • the cmdlet markdown files were generated using the platyPS module

[MikhailTryakhov]

@praries880 @maddieclayton according to #7118 it received LGTM
@khannarhea please work on comments mentioned (change log), double check SDK is set to 19.4.0 and tests are passed, no new conflitcs...

[praries880]

@khannarhea

The LB tests will need to re re-recorded.

Failures: https://azuresdkci.westus2.cloudapp.azure.com/job/powershell/7478/artifact/src/Publish/TestResults/FailingTests/Microsoft.Azure.Commands.Network.Test.dll.html

https://travis-ci.org/Azure/azure-powershell/builds/427835583#L1660

[khannarhea]

@praries880 - updated recordings

[praries880]

Retrying Jenkins build because of randon test failure in service management

[praries880]

@khannarhea kindly take care of merge conflicts

[khannarhea]

resolved merge conflicts