Offer split tunneling or app permissions feature on all Mozilla VPN platforms

[chrismore]

Currently, the split tunneling feature only exists on the Android platform, which is called "app permissions" in the settings. This is a common feature for VPNs and it should be available across all platforms we offer today.

We do have issue #416 already fixed on Android, which defines an allow-list as Android has many "system apps" that users would likely never interact with. Some of those system apps are common Google apps like Gmail. The allow-list defines, which system apps we should display in the UI.

• [x] windows #922
• [x] android
• [x] Linux - https://github.com/mozilla-mobile/mozilla-vpn-client/issues/842
• [ ] macos - https://github.com/mozilla-mobile/mozilla-vpn-client/issues/843
• [x] ios -currently not implementable

┆Issue is synchronized with this Jira Task

[birdsarah]

Do we want this to be informed by the anti-profile linking discussions?

[Cimbali]

Linux is really only partially supported, see #1869

[Cimbali]

In fact, while the apps permission interface works on Linux, the actual split-tunnelling seems to not work at all on Ubuntu 20.04 and other Linux platforms, see #6394