[plug-in]Apply code action does not work

[svor]

While using java VS Code extension I found that ApplayCodeAction command does not work.
Looks like this issue related to commands API. Here I see 2 problems:

1. When a command from code action is transforming to internal Command by https://github.com/theia-ide/theia/blob/master/packages/plugin-ext/src/plugin/type-converters.ts#L404. The problem is here
   because Command from vscode.d.ts is not identical with Command from theia.d.ts.

2. There are no way to register a command from the plugin as global. By global i mean that registered command should be available not only in plugin-system. It means that commands which were provided by plugins will be visible in Theia scope to make it possible execute them.

[svor]

Fixed by #4021