feat(Settings): add option to disable context menus

[sleistner]

Description

A new configuration section has been added which selectively allows to show or hide commands in the explorer, editor and editor title context menu.

Fixes #380

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[sleistner]

🎉 This PR is included in version 3.10.0 🎉

The release is available on:

• Visual Studio Marketplace
• GitHub release

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