chore: Angular upgrade to v10

[ziacik]

Hi. This is an upgrade to latest Angular 10. Some changes had to be done besides automatic migrations:

1. Removed HttpModule import which was deprecated.
2. Updated graph component template to use public options property instead of private (didn't compile otherwise).
3. In Link, changed source and target declaration to just Node. Otherwise the link-visual component which uses link.source.x wouldn't compile. It's not quite right as the source and target props are still initialized with numbers, didn't find another way though and everything compiles and works, so...