Use Cmdliner to parse CLI in tools

[jubnzv]

We could use Cmdliner instead of the manual parsing of CLI argument.

This will allow us to:

• Add parametrized options more easily.
• Generate man pages automatically. Here is an example: https://github.com/mtt-lang/mtt-lang/blob/master/man/dune.

But we should keep the current CLI syntax, so that the miners do not have to upgrade their scripts.

[jubnzv]

Duplicate #1152

[anton-trunov]

We started using Cmdliner for the Scilla formatter scilla-fmt: it looks great, although, it uses double dashe -- for long CLI arguments and the Scilla checker and runner use single dash -.