Add support to run remote template

[parrasajad]

• Add remote-template-domain config only flag to specify allowed domain list to load remote templates from

Proposed changes

Checklist

• Pull request is created against the dev branch
• All checks passed (lint, unit/integration/regression tests etc.) with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[ehsandeep]

Requires go mod update to fetch changes from goflags

[forgedhallpass]

Since this is a sensitive feature that can lead to potential vulnerabilities if not implemented correctly, it is important to have extensive tests with multiple scenarios, especially negative.

[ehsandeep]

Currently RemoteTemplateDomainList validation cheks only when loading single remote template with YAML extension and not when loading remote template with list input, we need to enforce the validation for 2nd input as well.