Create accounts & deployments in `flow init`

Issue To Be Solved

flow init is an effective way to instantiate a Cadence project so that developers can begin writing Cadence with a single command. However, in order to deploy their contracts, the developer must still create accounts and configure deployments in their flow.json, which can be burdensome.

(Optional): Suggest A Solution

To reduce friciton, flow init can create accounts & configure a default deployment for the generated starter contract. flow project deploy --network=testnet (or mainnet) would then work out-of-box. This gives developers a 0-configuration path to create and deploy a contract with 2 commands.

The account creation could be parallelized for both testnet/mainnet & the total slowdown shouldn't be more than ~8s. Users who wish to opt out should have the option to do so using a flag, e.g. --skip-deployments.

(Optional): Context

Reduce developer friction deploying contracts.

Start at the flow init command entry point and inspect the existing account-creation and deployment configuration commands. Verify the generated project can run flow project deploy --network=testnet or mainnet without manual setup, while an opt-out flag such as --skip-deployments prevents that setup.