Add config helper (WIP) and missed constants in existing dataloaders

[holylovenia]

• Derive SEACrowdConfigHelper from NusantaraConfigHelper. Basic function works but haven't modified SEACrowdMetadataHelper, constants, etc.
• Add some missed constants (e.g., _LANGUAGES and _LOCAL) found during the config helper creation.

[SamuelCahyawijaya]

LGTM!

[sabilmakbar]

init review, for the constant missed I'll cross-check it with my checker & fix (prob will add the check script here too if needed)

[sabilmakbar]

are we going to update it later? or we just write it as-is from NusaCrowd?

[holylovenia]

Will update later! Might also deprecate this function depending on its use case. Do you have any suggestion regarding this?

[sabilmakbar]

prob we can change the value according to the SEACrowd Dataset Size Info. But since NusaCrowd v1.0 is a subset of SEACrowd, we can keep it as-is for now and update it later

[sabilmakbar]

will we add SEACrowd-based Benchmark to this later? or could it be done on this review since the dataset picking has been done

[holylovenia]

@sabilmakbar Yes yes. I'll add it on the next PR since we're still reviewing some of the speech dataloaders.

[sabilmakbar]

and for benchmark, we can use the datasets used for SEACrowd Experiment, hence the value should be overriden from NC

[sabilmakbar]

btw @holylovenia is the config still on WIP?