add log for number of target nginx replicas

[OliverMKing]

Description

Adds a log printing the number of desired nginx replicas. Useful for informing us if customer manually changes the number of replicas to 0 and records what the HPA is doing.

Type of change

Please delete options that are not relevant.

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How Has This Been Tested?

Locally

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules

[coveralls]

Pull Request Test Coverage Report for Build 7025109650

• 0 of 3 (0.0%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.09%) to 80.893%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/controller/nginxingress/nginx_ingress_controller.go	0	3	0.0%
<!--	Total:	0	3	0.0%	-->

Files with Coverage Reduction	New Missed Lines	%
pkg/controller/ingress/concurrency_watchdog.go	1	86.41%
<!--	Total:	1		-->

Totals
Change from base Build 7024440125:	-0.09%
Covered Lines:	2989
Relevant Lines:	3695

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💛 - Coveralls