Feature: Validate cluster addition

[kartik-579]

🔖 Feature description

Devtron uses cluster validation by argocd but does not provides one on its own. This makes cluster to be added without validation in case when gitops is not configured or in case of EA mode. Cluster should be validated across all cases.

🎤 Pitch

Without being validated, cluster addition causes a lot of inconvenience to user since a user will only know about the incorrect configuration when using the cluster (let us say deploying on an environment) and also it is highly likely that it won't be possible for the user to not understand the reason.

✌️ Solution

Implement validation when adding a cluster independent of the gitOps configuration.

🔄️ Alternative

NA

👀 Have you spent some time to check if this issue has been raised before?

• I checked and didn't find similar issue

🏢 Have you read the Code of Conduct?

• I have read the Code of Conduct

AB#635