Make `bolt-sidecar` package a Cargo workspace

[thedevbirb]

Currently the bolt-sidecar is one big crate. As the project is becoming more and more mature there are some components (like the primitives) that should become separate crates so that can be used by other projects as dependency.

For a guideline, every folder under bolt-sidecar/src could become a separate crate.

[mempirate]

Would start with just bolt-common and bolt-primitives, i.e. the once we know would be used by other projects like registry, RPC etc.

[0ex-d]

What do you think of workspace dependency alias? I can work on this, incrementally move src/common -> crates/common.

[workspace.dependencies]
bolt-common = { path = "./crates/common" }
bolt-primitives = { path = "./crates/primitives" }

[0ex-d]

Taking further look, here are some options, to support backward compatibility and other open PRs:

1. Rename bolt-sidecar -> bolt-sidecar-legacy then make bolt-sidecar a workspace.
2. Leave bolt-sidecar unchanged and create new workspace like bolt-sidecar-workspace.
3. Gradually move packages in bolt-sidecar/src to bolt-sidecar/crates:
   a. most binaries/lib here depend on each other. (E.g bolt-common <- bolt-primitivies <- bolt-cypto <- bolt-state), might as well move all of them anyway.
   b. In Cargo.toml might have [package] and [workspace.package]

Legend:
<- : dependencies

These solutions may entail duplicated code for CI/CD.

Let me know your thoughts on this.