tvOS push support

[toto]

This is a continuation of an old PR for tvOS support: #1238

This is important since tvOS does now support a few of APNS push features:

• background refresh (aka content-availible)
• setting a badge

The code has been tested end to end and does work for both conditions using a vanilla parse-server. Note the config section below though.

Changes

• Mostly allows PFInstallation and friends to be used on tvOS by removing unavailable markers.
• Takes into account that tvOS has a applicationBadge now as well. So the logic for that should also work on tvOS as well.
• Since tvOS apps also can have extensions (namely top-shelve extensions) also allow
  containingApplicationBundleIdentifier and applicationGroupIdentifier.
• deviceType for Apple TV apps is now tvos not appletv to make it compatible with the current parse-server-push-adapter

Config

To make pushes to tvOS work, a section tvos needs to be added to the parse-server config. It should look exactly like the ios section. This should probably be added to the parse-server docs.

Notes on other Parse components

• parse-server-push-adapter uses tvos as a deviceType (see here: https://github.com/parse-community/parse-server-push-adapter/blob/e7f9bc45339ed8bcbb7dfca9d092e54bddeee95c/src/ParsePushAdapter.js#L28). Therefore this PR changes the registration of tvOS devices to tvos from appletv
• I also plan to add a PR for parse-dashboard so you can target tvos via the GUI: Add tvOS support to push targeting parse-dashboard#936
• Also I will add a PR for the docs update once this is merged: Improve docs for tvos docs#577

[toto]

@flovilmart Any idea whats wrong with the macos CI build? The rest i could reproduce and fix but this one I can't make heads or tails of. It seems only the keychain related tests fail. They run fine on two macs I tried them on.

[flovilmart]

Not sure why they fail, requires a deeper investigation / changing the perhaps the toolchain for testing. For now we can ignore I think. I’ll give a look to your patch over the weekend.

[flovilmart]

Ok, so because there is no CI test of the tvOS, we cannot asses this works as expected. I assume you have some example working of edge to edge tests @toto?

[toto]

@flovilmart I have an installation with ~1.6k devices running iOS and tvOS successfully registering and pushing. I will also test macOS just be sure

[flovilmart]

@toto this is awesome!!!!

[flovilmart]

Thanks for getting it in!

[toto]

@flovilmart Also added the PR for a tiny docs improvement. Would have saved me an hour of digging though the server source code: parse-community/docs#577