Tta 63 fix args types

[ryancwalsh]

See https://near-foundation.atlassian.net/browse/TTA-63

This PR:

• deletes getArgsAsObjectUsingBase64Fallback since NEAR Protocol in Rust already populates the args_json field from args_base64 when possible
• moves type definitions to index.d.ts
• cleans up ActionReceiptActionArgs type
• moves convertYoctoToNearAndConsiderSmallAmountsToBeZero and getFinalCsvRow into transformations.ts
• moves divideByPowerOfTen to external/fungibleTokenTools.ts (a placeholder for functions that are not specific to this repo and can be moved into an external library)
• labels the datetime_utc as such (it's always important to be clear about time zones, and I'm not sure why the HH:mm:ss had gotten removed)
• moves the datetime helper out to external (temporary location)
• uses the official "utils" from near-api-js for conversion instead of us defining our own export const YOCTO_CONVERSION_CONSTANT = 10 ** 24;
• adds some comments warning about precision loss
• removes ACCOUNT_IDS from .env since that dev-only feature is no longer useful now that we're using localStorage