fix: ensure that PbxGroups are not duplicated

[jcassidyav]

This tracks the PbxGroups that are created, to ensure that duplicates are not created while also allowing for the scenario as described in #15 addressing NativeScript/nativescript-cli#5765.

It tracks the groups in an external file so that you can edit the project in XCode and still maintain the link.

[jcassidyav]

@rigor789 I think this will satify the original issue in #15 and the reciently reported duplication issues in the project.

[rigor789]

Interesting approach - we can give it a go for sure! I was also wondering if we could store this in the pbxproj itself, but I imagine XCode may clean it up if it's an unknown entry...

Interestingly we could also store it as comments above the groups I guess - but anyways these are just ideas, storing in a separate file should be totally fine too.

[jcassidyav]

Yeah unfortunatly once you do anything, say rename a file the pbxproj gets cleaned up.

Of course editing the project in xcode is probably not that common a thing to do.

[rigor789]

Ah that's unfortunate - renaming in XCode shouldn't break it, so no-go on that!