[electron][macOS] The Preferences menu should belong to the main application menu not File

[kittaakos]

Description

As a macOS user, I would expect the Preferences Settings menu item under the 0 index, not under File. See, it is the same in VS Code:

In a Theia-based app, the Preferences in under File:

However, on Windows and Linux, it should go under File:

Note, Open Preferences should be renamed as well.

Reproduction Steps

OS and Theia version:

Diagnostics:

[joewiz]

Agreed. As a longtime Mac user, I find it confusing that Theia-based apps lack a Preferences item inside the app menu. As an example of the correct behavior, see these cross-platform apps:

Chrome

Discord

Atom

Slack