Extend failure models to allow more fine-grained error handling modes

[pharr117]

The app currently only provides a single FailedBlock model:

cosmos-indexer/db/models.go

Lines 20 to 25 in b6ce455

	type FailedBlock struct {
	ID uint
	Height int64 `gorm:"uniqueIndex:failedchainheight"`
	BlockchainID uint `gorm:"uniqueIndex:failedchainheight"`
	Chain Chain `gorm:"foreignKey:BlockchainID"`
	}

This model is used at a global error catching level, any error that happens in the main indexer loop marks the entire block as failed.

We want to extend the failure modes by providing ALL of the following:

1. FailedBlock
2. FailedTransaction
3. FailedMessage

We will then be able to extend the possible failure modes so that we can index the other transactions in a block even if one fails.