WIP auto install tools

[cbandera]

Description

This PR introduces a tool manager that is able to download tools on demand.

• A central JSON config defines the tools, their repos, the version and expected shas to download.
• This assures that we can control which version of a tool is to be used with a given release
• Versions are pinned and hashsums are verified to avoid security risks
• Renovate is used to automate the update of tool versions during development - just like any other dependency.
• CI uses the same config file and tool versions for testing.
• Upon startup the extension prompts the user for download, if a tool can not be found.

Related Issue

• Related to Implement language server for Starlark #1
• Closes Auto-install tools #371

Testing

• Tests added/updated
• Manual testing performed

Checklist

• Code follows the project's style guidelines (prettier/eslint)
• Commit messages follow Conventional Commit conventions
• Tests pass locally (npm run test)