LanguageClient ID. And, use node script to copy yaml file.

[sfdctaka]

What does this PR do?

Implemented feedback from last PR.

• Updated LanguageClient's ID.
• Use node script to determine the platform(Windows vs Unix) where it is running and run appropriate copy command.

[khawkins]

One more change to be made: line 103 of package.json needs to be updated from:

        "bundle:extension": "esbuild ./src/extension.ts --bundle --outdir=out --format=cjs --target=es2020 --platform=node --external:vscode --external:@salesforce/core --external:@oclif/core --external:@salesforce/lwc-dev-mobile-core --minify --sourcemap",

to:

        "bundle:extension": "esbuild ./src/extension.ts --bundle --outdir=out/src --format=cjs --target=es2020 --platform=node --external:vscode --external:@salesforce/core --external:@oclif/core --external:@salesforce/lwc-dev-mobile-core --minify --sourcemap",

--outdir needs to be updated to the new output location.

[sfdctaka]

Added package-lock.json which was supposed to be in the last PR.