Port and organize Ethereum examples

[dliuproduction]

• Implement Ethereum versions of samples when available

• Migrate public github example repos to docs repo

• [x] example-graphql-grpc

• [x] example-search-ethereum

• [x] example-stream-ethereum

• [x] example-stream-transfers (eos)

• [x] example-dfuse-events

• [x] example-stream-action-rates (eos)

• [x] example-transaction-lifecycle (eth)

• [x] example-graphql-apollo

• [x] example-graphql-apollo-stats

• [x] example-graphql-python

• [x] example-eos-rex-price-feed

• [x] example-push-notifications

• [x] example-dfuse-events-contract

• [x] example-node-server

• [x] example-eosjs-decode-hex

• [x] example-push-guaranteed

• Migrate advanced examples from client.js to docs

To Review: https://github.com/dfuse-io/client-js/tree/master/examples/advanced

[dliuproduction]

EOS examples to implement for Ethereum:

• [ ] graphql-grpc-go
• [ ] graphql-grpc-python
• [ ] graphql-apollo
• [ ] dfuse-events?
• [ ] push-notifications-go
• [ ] stream as tutorial (to cover three core products: search, lifecycle, stream)