This PR replaces webpack with esbuild, as our bundler.
The change leads to out-of-the-box ~5x improvement in bundling times, reducing the latency in watch-based workflows.
Along with this a new development server (with live reload capacity) has been introduced to support watch command.
[ci no changelog needed]
### Important Notes
* workflow for checking docs has been removed because it was using outdated prettier version and caused troubles; while the same check is performed in a better way by the GUI/Lint job.
* introduced little more typescript in the scripts in place of js, usually with minimal changes.
* The bash entry point was renamed `run.sh` -> `run`. Thanks to that `./run` works both on Linux and Windows with PowerShell (sadly not on CMD).
* Everyone's favorite checks for WASM size and program versions are back. These can be disabled through `--wasm-size-limit=0` and `--skip-version-check` respectively. WASM size limit is stored in `build-config.yaml`.
* Improved diagnostics for case when downloaded CI run artifact archive cannot be extracted.
* Added GH API authentication to the build script calls on CI. This should fix the macOS build failures that were occurring from time to time. (Actually they were due to runner being GitHub-hosted, not really an OS-specific issue by itself.)
* If the GH API Personal Access Token is provided, it will be validated. Later on it is difficult to say, whether fail was caused by wrong PAT or other issue.
* Renamed `clean` to `git-clean` as per suggestion to reduce risk of user accidently deleting unstaged work.
* Whitelisting dependabot from changelog checks, so PRs created by it are mergeable.
* Fixing issue where wasm-pack-action (third party) randomly failed to recognize the latest version of wasm-pack (macOS runners), leading to failed builds.
* Build logs can be filtered using `ENSO_BUILD_LOG` environment variable. See https://docs.rs/tracing-subscriber/0.3.11/tracing_subscriber/struct.EnvFilter.html#directives for the supported syntax.
* Improve help for ci-run source, to make clear that PAT token is required and what scope is expected there.
Also, JS parts were updated with some cleanups and fixes following the changes made when introducing the build script.
