Simple blockchain explorer views for Skycoin

**Feature description**

Blockchain block explorer

**Is your feature request related to a problem? Please describe.**
It is not possible to see blocks and corresponding transactions

**Describe the solution you'd like**
Choose coin and display blocks list . Zoom details and navigate up to transaction level.

**Additional context**
The following web sites can be considered as reference

- [Ethplorer](https://ethplorer.io/) . It offers an [explorer API](https://github.com/EverexIO/Ethplorer/wiki/Ethplorer-API)
- [Etherchain](https://www.etherchain.org/)
- [Skycoin explorer](https://explorer.skycoin.com)
- [Etherscan](https://etherscan.io) . Check out the [APIs](https://etherscan.io/apis)
- [Blockchain.com](https://www.blockchain.com/explorer)
- [BTC.com](https://btc.com/)

Transaction details should have been implemented already , see #19 #216 #238

**Possible implementation**

- [ ] Latest blocks
- [ ] View all blocks (with pagination)
- [ ] Block detail
- [ ] Latest confirmed transactions
- [ ] Add miner details e.g. [Spark Pool](https://etherscan.io/address/0x5a0b54d5dc17e0aadc383d2db43b0a0d3e029c4c)
- [ ] Link to transaction details
- [ ] Input and output details