Add support for deploying and testing on devnet

[zees-dev]

Description

There is a devnet - generally to which changes are rolled out first; before hitting testnet and mainnet.
Sometimes the fuel core client has breaking changes - which can only be tested on devnet for a considerable amount of time.
In such cases it would be very useful if we can use the sway playground to deploy contracts directly to devnet.

The devnet URL is: https://devnet.fuel.network

curl -X POST 'https://devnet.fuel.network/v1/graphql' \
  -H 'Content-Type: application/json' \
  -d '{"query": "{ chain { latestBlock { header { height } } } }"}'

The devnet faucet URL is: https://faucet-devnet.fuel.network