cli: oasis rofl init

[matevz]

Following https://docs.oasis.io/rofl/prerequisites is pretty demanding. Could we ask people to install the Oasis CLI on their platform and then simply run oasis rofl init to install all dependencies etc. based on their OS (or expect them to have docker installed and install the rofl-dev image). Also populate the project with a simple ROFL example rust code, solidity contract and add rofl.yml.

ps. Check out similar helpers such as forge init, hardhat init, cargo init, npm init for more ideas.

[kostko]

It would probably be easier to just use a predefined container for building, with all dependencies already installed. Otherwise it will be a pain to get right for all possible combinations.