Move all Sorbet related commands as subcommands

[Morriar]

Currently, all the commands are top level making both the code and DX a bit messy. I also want to make some space for other commands such as the deadcode related ones.

Those are the commands currently merged:

  spoom bump            # Bump Sorbet sigils from `false` to `true` when no errors
  spoom coverage        # Collect metrics related to Sorbet coverage
  spoom lsp             # Send LSP requests to Sorbet
  spoom tc              # Run Sorbet and parses its output

With this change, all commands related to Sorbet are moved under the parent command srb:

  spoom srb bump            # Bump Sorbet sigils from `false` to `true` when no errors
  spoom srb coverage        # Collect metrics related to Sorbet coverage
  spoom srb lsp             # Send LSP requests to Sorbet
  spoom srb tc              # Run Sorbet and parses its output

To avoid breaking right now, I kept the top level commands to redirect to the srb ones with a deprecation message:

$ bundle exec spoom tc
Warning: This command is deprecated. Please use spoom srb tc instead.

We can remove them in the later major version bump.

[andyw8]

People may wonder if the new one is the same or not. Would it be better to say it's been 'renamed' or 'moved'? Or we could append, "...instead, which has identical behavior".

[Morriar]

Do you think the release notes would be enough?

[andyw8]

Maybe, but I suspect few people read them.

[andyw8]

(my comment is non-blocking)