Improve one-shot CLI

[petkodes]

Problem statement
The current one-shot CLI is perfect for sending one-off subgraph versioning update messages (as well as any message really, with a few tweaks), but we need it to be more user-friendly. This means possibly changing its name and adding a script that runs it within Docker, eliminating the need for users to install all pre-requisites like Go, Clang, etc. We also need to extract it to a separate repo.

Expectation proposal
Users (subgraph devs) should ideally be able to pull a Docker image (GHCR package) and run it with custom arguments.

Alternative considerations
We could also skip this and instead wait for graphcast-web to be functional before recommending the subgraph versioning feature to subgraph developers, but that will take a lot longer and getting early feedback is vital.