Allow skipping upstream TLS server certificate validation for the webhook proxy functionality

[Oded-B]

Description

Allow skipping upstream TLS server certificate validation for the webhook proxy functionality Use-case: Handeling PKI to allow verification of TLS in in-cluster(k8s) services (https://argocd.argocd.svc.cluster.local) is hard. Some services don't provide an easy way to expose both TLS and plaintext endpoint without redirecting the traffic to the TLS endpoint and Webhook payloads are relitivly low risk so skipping TLS verification might make sense for some users.

Type of Change

• [ ] Bug Fix
• [X] New Feature
• [ ] Breaking Change
• [ ] Refactor
• [ ] Documentation
• [ ] Other (please describe)

Checklist

• [x] I have read the contributing guidelines
• [ ] Existing issues have been referenced (where applicable)
• [x] I have verified this change is not present in other open pull requests
• [x] Functionality is documented
• [x] All code style checks pass
• [ ] New code contribution is covered by automated tests
• [x] All new and existing tests pass