JSON-RPC stdio server

[link2xt]

deltachat-rpc-server is a binary that speaks JSON-RPC protocol (the same as currently used by DeltaChat Desktop to interact with the core) over stdio. Requests are sent over stdin, responses and event notifications are printed on stdout, one JSON dictionary per line. This is similar to how Language Server Protocol works when Visual Studio Code or Emacs talks to clangd or rust-analyzer, actually even simpler.
There is also an example python script in this PR that spawns a deltachat-server and calls a few methods asynchronously (via async-await). The plan is to move it into a separate deltachat-client python package.
Advantages over existing Python bindings are:

• No deltachat-ffi on the core side (unsafe Rust code) is used, deltachat-server is written completely in safe Rust except unavoidable low-level dependencies. If it crashes, at least it's not our fault. It is hard/impossible to crash it from Python even if you try to.
• No dependencies on the Python side. We only use built-in json and asyncio libraries to spawn the process and exchange JSONs. It means pypi package can be uploaded to pypi without rebuilding it for each architecture
• Core is easy to update and statically linked deltachat-rpc-server binary can be distributed separately, you just need to throw it somewhere in the $PATH.
• Unlike deltachat-ffi blocking calls, this approach is async all the way down. Python is using asyncio and JSON-RPC calls are async rust functions. If a call to library is slow, for example because bot did an expensive database query while processing an incoming message, bot does not block waiting for the reuslt, but processes messages of other users.

[link2xt]

Added an example that creates an account, but we need to fix deltachat/yerpc#6 first before JSON-RPC is usable (fix deltachat/yerpc#22 is waiting for review).

[flub]

rust 1.64 allows this to be done using workspace.package. not sure how eagerly we upgrade these days, and in any case probably not something for this PR

[flub]

is it worth handling the potential KeyError that could be raised here?

[flub]

fwiw might be worth using tracing for new things instead of env_logger

[link2xt]

This PR is ready for review, JSON-RPC node tests are ported from WebSocket to this stdio server. Python client is moved into #3734.

[flub]

oh, nice! didn't realise this would completely eliminate the Arc and RwLock, that makes it certainly better.

[link2xt]

@Simon-Laux @Jikstra
Do you have any comments on JS part of this? Not sure if my code is ok, e.g. when I should call super(), if it's ok to pass stdin/stdout like this etc.

I tried to keep things compatible and avoid breaking WebSocket example, so things are named to avoid conflicts with existing DeltaChat class.