Generate different .vscode/setting for different config profile

[chenyukang]

The idea is from rust-lang/rustc-dev-guide#1890

I'm always feeling slow when editing the source code in rustc, today I spent some time to tweak my settings, and I found one reason is rust-analyzer.check.overrideCommand.

On my dev machine x check will spend about 4s, so it's not acceptable if it's executed multiple times.
It will cost about more than 4x time to run x check compared with x check compiler.

Maybe we can generate different .vscode/setting.json for different config profile?