chore: Delete generated aar files

[farfromrefug]

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What is the current behavior?

What is the new behavior?

Fixes/Implements/Closes #[Issue Number].

[NathanWalker]

Appears widgets-release.aar needs to stay since ui-mobile-base is not built with npm release, prebuilt to save time, but core.aar may can be removed.

[CatchABus]

@farfromrefug It seems that core.aar was not purposely generated. I think it might be a result of a build in NativeScript/apps? Not sure.
We could remove core.aar and add a gitignore rule for it to make sure nobody commits it again in the future.

[farfromrefug]

@NathanWalker it should be best to rebuild it on each npm release to ensure we are up to date with sources. I do that in my fork without any issue

[farfromrefug]

@CatchABus indeed I will add a gitignore