chore: merge release in master

[VladimirAmiorkov]

• release: cut the 8.0.0 release

• chore: update changelog with migration steps for Angular 7.x.x to Angular 8.0.0

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• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
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• Tests for the changes are included.

What is the current behavior?

What is the new behavior?

Fixes/Implements/Closes #[Issue Number].

[VladimirAmiorkov]

test ignore