Refactor Instance Watcher

[aphralG]

Proposed changes

This PR removes each instance having its own Instance operator and health watcher.
It also moves the logic for updating the resource into the instance watcher to reduce the amount of messages being sent on the bus.
The resource plugin has been remnemed to the nginx plugin as it now only has logic to apply, relaod and validate the nginx config.
NAP no longer has its own instance watcher, the nap instance watcher is now started in the instance watcher and is checked for updates when we check for instance updates reducing complexity and the number of messages being sent.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• I have run make install-tools and have attached any dependency changes to this pull request
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• If applicable, I have updated any relevant documentation (README.md)
• If applicable, I have tested my cross-platform changes on Ubuntu 22, Redhat 8, SUSE 15 and FreeBSD 13

[codecov]

Codecov Report

❌ Patch coverage is 75.28090% with 66 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.54%. Comparing base (02f4c36) to head (af3b01a).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...ernal/watcher/instance/instance_watcher_service.go	76.08%	17 Missing and 5 partials ⚠️
internal/nginx/nginx_plugin.go	67.24%	19 Missing ⚠️
internal/nginx/nginx_service.go	72.88%	15 Missing and 1 partial ⚠️
...her/instance/nginx-app-protect-instance-watcher.go	83.78%	5 Missing and 1 partial ⚠️
internal/watcher/health/health_watcher_service.go	57.14%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1490      +/-   ##
==========================================
- Coverage   85.13%   84.54%   -0.59%     
==========================================
  Files         102      102              
  Lines       13217    13199      -18     
==========================================
- Hits        11252    11159      -93     
- Misses       1475     1547      +72     
- Partials      490      493       +3     

Files with missing lines	Coverage Δ
internal/nginx/nginx_instance_operator.go	91.17% <ø> (ø)
internal/nginx/nginx_instance_process_operator.go	61.76% <ø> (ø)
internal/nginx/nginx_log_tailer_operator.go	86.66% <ø> (ø)
internal/nginx/nginx_plus_actions.go	97.60% <100.00%> (ø)
internal/plugin/plugin_manager.go	88.23% <100.00%> (ø)
internal/watcher/watcher_plugin.go	69.76% <100.00%> (-3.15%)	⬇️
internal/watcher/health/health_watcher_service.go	44.89% <57.14%> (-44.20%)	⬇️
...her/instance/nginx-app-protect-instance-watcher.go	80.00% <83.78%> (-2.69%)	⬇️
internal/nginx/nginx_service.go	59.74% <72.88%> (ø)
internal/nginx/nginx_plugin.go	77.67% <67.24%> (ø)
... and 1 more

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[dhurley]

Suggested change

	slog.DebugContext(ctx, "Updating resource")
	slog.DebugContext(ctx, "Updating resource", "resource", resource)