Node 8: Add legacy API endpoints

[osagga]

This will add some of the endpoints that were not added in v8, but were in v3-v5.

• Added api/tx/:txid/raw to get the raw hex value of the transaction specified by txid
• Added api/block/latest to get the latest block stored on the bitcore-node of the specified blockchain.

[micahriggan]

@osagga thanks for contributing

We're doing active development in the mono-repo here:

https://github.com/bitpay/bitcore/tree/v8.0.0

We need to have a note on this repo that active development has moved there. I'll do that tomorrow.

One thing I'm not sure about, is exposing the RPC for retrieving data. Is there some data you're wanting that the current mongo model isn't storing?

Thanks again

[osagga]

Thanks for the help, a note about the other repo in this one would have been helpful.

The main data that I'm interested in is the raw hex transaction. In the previous versions of the node, it used to be a separate endpoint for rawTx. The raw transaction can used as a common way to initialize a Transaction object in various bitcoin libraries, that's why it's really helpful.

About exposing the RPC, I'm doing it in the same way /tx/send exposes the RPC interface, I don't see how can that be harmful?

I can move this PR to bitcore/bitcore if you want. Let me know what do you think.

Thanks