feat: Configurable sync policy for ArgoCD

[mile-misan]

What does this PR do?

This PR adds parameter for sync policy in the application helm template. Default values stayed the same but now they are defined in values.yaml of app-of-apps chart.
Sync policy can be controlled in 2 ways:

• for all applications by changing default values
• per application by overriding default values in apps section, for example, to use manual sync omit automated section in the sync policy definition:

  istio-ingressgateway:
    name: istio-ingressgateway
    path: addons/istio/ingressgateway/
    targetNamespace: istio-ingress
    syncPolicy:
      syncOptions:
        - CreateNamespace=true

Also, this PR moved istio-ingress out of Istio sync-wave which removed the need to use namespace manifest for istio-ingress app.

Related issues

Closes #39

Checklist before merging

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have checked the contributing document.
• I have checked the existing Pull Requests to see whether someone else has raised a similar idea or question.
• I have added tests that prove my fix is effective or that my feature works.
• I have upgraded the changelog according to the nature of the feature that I am adding to this Pull Request.

[julianxhokaxhiu]

LGTM - Thank you!