[v2] Add support for optional fields for config struct

[yurishkuro]

Looking for a volunteer to add support for optional fields for config structs.

• Main issue: https://github.com/open-telemetry/opentelemetry-collector/issues/10266
• Prototype: https://github.com/open-telemetry/opentelemetry-collector/pull/10260
• which is blocked by: https://github.com/go-viper/mapstructure/issues/37

Objective: create a draft PR with a prototype solution outlined in https://github.com/go-viper/mapstructure/issues/37 (make sure it's a draft to avoid creating notifications noise to go-viper maintainers). Update this ticket with a link so that we can collaborate on that prototype.

[nag0yan]

@yurishkuro Hello. Can I try this issue?

[yurishkuro]

You don't need to ask

[mahadzaryab1]

@yurishkuro opened a draft at https://github.com/go-viper/mapstructure/pull/42. Let me know if you have any feedback and I'd be happy to incorporate it in.

[akstron]

Hi @mahadzaryab1 I think this issue can be closed since your PR got merged?

[yurishkuro]

issue is not solved