This change replaces an sqllite-backed suggestions' repo with a simple, in-memory, one.
As `completion` functionality has been implemented completely in GUI, there is no need to support it in backend, which simplifies a lot of functionality.
Closes#9650 and #9471.
# Important Notes
Loading suggestions and sending them to GUI on startup is almost instantaneous. Previously it would take ~10s just for `Standard.Base`.
There are two projects transitively required by `runtime`, that have akka dependencies:
- `downloader`
- `connected-lock-manager`
This PR replaces the `akka-http` dependency in `downloader` by HttpClient from JDK, and splits `connected-lock-manager` into two projects such that there are no akka classes in `runtime.jar`.
# Important Notes
- Simplify the `downloader` project - remove akka.
- Add HTTP tests to the `downloader` project that uses our `http-test-helper` that is normally used for stdlib tests.
- It required few tweaks so that we can embed that server in a unit test.
- Split `connected-lock-manager` project into two projects - remove akka from `runtime`.
- **Native image build fixes and quality of life improvements:**
- Output of `native-image` is captured 743e167aa4
- The output will no longer be intertwined with the output from other commands on the CI.
- Arguments to the `native-image` are passed via an argument file, not via command line - ba0a69de6e
- This resolves an issue on Windows with "Command line too long", for example in https://github.com/enso-org/enso/actions/runs/7934447148/job/21665456738?pr=8953#step:8:2269
