Rename this tool to `mm-release`?

There are a couple of tickets which talk about adding new functionality that would not run automatically as part of the main workflow but only when requested:

- https://github.com/MetaMask/create-release-branch/issues/110
- https://github.com/MetaMask/create-release-branch/issues/108

To accomplish these, we may want to extend the CLI and introduce commands to this tool. We'd still have a default command for the existing workflow now so as not to break backward compatibility, but then we'd introduce commands for the two tickets above.

If we do this, then we may want to rename this tool to encapsulate the increase in scope. Perhaps we call it `mm-release`?

Zooming about a bit, we've been talking about creating a unified tool for all things MetaMask, so if we called it `mm`, then we could implement a Git-style interface such that `mm ` would map to `mm-`. This would allow us to develop extensions to `mm` in independent repos and they would "just work". For instance, we could rename `template-sync` to `mm-template-sync`, and we could even create a new tool to make it easy to create a new repo based on the module template (`mm-repo`?). Naming _this_ tool `mm-release` would fit into this plan.

Start by reviewing the proposed functionality in issues #110 and #108, then inspect the current CLI and its default workflow. Determine whether the tool should be renamed to mm-release or become part of a broader mm command structure, while preserving backward compatibility. Done means the naming and command-extension direction is agreed and actionable.

Written by the indexing model from the issue text.