Debugging: tracking issue for MVP and post-MVP work

The "MVP release" of the user-facing guest-debugging feature in Wasmtime is pretty close now, and requires:
- [x] #12756: the environment in which debug components run
- [x] #12771: the built-in gdbstub component, usable via `wasmtime run -g`
- [x] webassembly/wasi-sdk#614 and corresponding release: a release of wasi-sdk with LLDB containing all necessary features
- [ ] update documentation to describe the guest-debugging flow

Post-MVP we have the following functionality queued up in some order:
- [x] #12776: debugging under `wasmtime serve`
- [ ] #12188: memory watchpoints
- [ ] "mutable debugging": the ability to inject calls, force early returns, and update locals/operand-stack values
- several levels here; the last two don't have gdbstub commands and aren't really necessary to change source-level locals in debug/non-opt Wasm component builds
- [ ] record/replay and debugging of replayed traces (cc @arjunr2)
- [ ] Store snapshots and reversible debugging
- [ ] debug-adapter DAP world, top-level DAP multiplexer, and adapter components for DWARF and for an interpreter