Allow bazel.executable to be set at workspace/folder level

[studgeek]

Attempting to set the bazel.executable setting for a workspace results in the error "This setting can only be applied in user settings in local window or in remote settings in remote window.".

However, it seems quite possible for a developer to need a different bazel executable for different projects (e.g. for google engineers - internal bazel tool vs bazel).

[yohcop]

Same thing for bazel.buildifierExecutable

[shaybarak]

I'd appreciate if this issue was addressed so that I could set up bazel.executable in my project's workspace.

While we're on the subject, it would help if it were possible to reference ${workspaceFolder} in the path.

[jfirebaugh]

While we're on the subject, it would help if it were possible to reference ${workspaceFolder} in the path.

This is https://github.com/bazelbuild/vscode-bazel/issues/132.