remove async/sync from CLI

[ricardogsilva]

Our CLI should not expose the underlying sync/async implementation details of its commands.

This means we will be free to implement commands in the most suitable way, and clients of the CLI would not need to worry about how the results are produced, only that they are correct.

With this in mind, let's remove all --request CLI options. Let's use the sync implementation under the hood for now - we may decide to switch it with the async one in the future (or even use a mixture, if that somehow would make sense).

Sometime in the future, when the project is more robust, we may want to bring this feature back. But for now let's remove it.