Complete main/0.52 indexer BaseApp Integration

[aaronc]

BaseApp currently has some basic integration with cosmossdk.io/schema/indexer but indexing of events, transactions, and block headers hasn't been done.

We need to add the relevant code here:

cosmos-sdk/baseapp/streaming.go

Lines 150 to 163 in 8431dbd

	func (p listenerWrapper) ListenFinalizeBlock(_ context.Context, req abci.FinalizeBlockRequest, res abci.FinalizeBlockResponse) error {
	if p.listener.StartBlock != nil {
	err := p.listener.StartBlock(appdata.StartBlockData{
	Height: uint64(req.Height),
	})
	if err != nil {
	return err
	}
	}
	//// TODO txs, events
	return nil
	}

The implementation should:

• correctly convert data from FinalizeBlockRequest into appdata.StartBlockData and appdata.TxData
• and convert the events from FinalizeBlockResponse inside FinalizeBlockResponse into appdata.EventData
• and call the appropriate StartBlock, OnTx and OnEvent functions on Listener

One challenge will be properly extracting the TxIndex, MsgIndex and EventIndex attributes for appdata.Event.

If possible, we should do some lightweight unit testing using mock data, with the understanding that more thorough testing end to end testing also needs to be done later.