Implement Sandbox CLI as a Go application

[minherz]

Description

Implement sandboxctl CLI in Golang. The implementation should have full feature parity with the existing CLI.
Further, CLI should support context management to allow launching new Sandbox and delete existing Sandbox when the project hosting it is provided.

The implementation should include full testing suite (unit testing, integration testing, etc.).

CLI should be able to work standalone without a need for explicit local clone of the Cloud Ops Sandbox repo.

[olivi-eh]

Commenting to reset SLO. Is this feature still planned / backlogged?