Export autoSync state of application

[gerardocorea]

Summary

Start to include the autoSync state of applications via metrics being exported.

Motivation

Using the provided metrics and autoSync state, teams can create dashboards or alerts based off if the autoSync policy of a application is set to disabled or not. Teams leveraging argoCD for gitops rely on the autoSync state of applications to be enabled always for the proper reconciliations of changes against repository that result in creation, modifications, or deletion of resources.

Proposal

If my brief understanding of this repository is correct we could append a label named autoSyncState to the metrics provided to prometheus with every scrape for every application that exists. This value would be set to true or false depending if autosync is enabled or disabled.

[gerardocorea]

I can volunteer to take this issue on if it's deemed possible and valuable.

[kexin-zhai]

+1. Would love to also have the ability to trigger argoCD notifications based on if the autoSync policy is manually disabled, especially after it has been set enabled on an application initially.