add default NginxIngressController reconciler

[OliverMKing]

Description

Adds a default NginxIngressController reconciler. This makes it so existing App Routing users have a smooth migration to the new CRD-based App Routing.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• 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?

E2e, unit, manually

Checklist:

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

[coveralls]

Pull Request Test Coverage Report for Build 6757420515

• 81 of 139 (58.27%) changed or added relevant lines in 5 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.5%) to 77.048%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/controller/nginxingress/nginx_ingress_controller.go	11	24	45.83%
pkg/controller/nginxingress/default.go	65	86	75.58%
pkg/controller/controller.go	0	24	0.0%

Files with Coverage Reduction	New Missed Lines	%
pkg/controller/controller.go	1	18.46%

Totals
Change from base Build 6756775295:	-0.5%
Covered Lines:	2699
Relevant Lines:	3503

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💛 - Coveralls

[OliverMKing]

/ok-to-test sha=67586c2