Fixes#1856

• switchparser to usescope-manager
  • I was able to delete almost all of the snapshots fromparser, because they were (pretty useless and unreviewed) snapshots of the scope tree from every singleshared-fixture.
• Fix up rules:
  • no-unused-vars
    • this exposedso many bugs in the tests themselves - so many unused generic type parameters (function foo<T>() {} andclass Foo<T> {}).
  • no-undef
  • no-shadow
    • define an extension rule to handlethis arg shadowing, and add an option for ignoring type/value shadowing.
  • no-redeclare
    • define an extension rule to handle function overloads
  • no-use-before-define

BASED ON#1939

BREAKING

This is a big change that will require action from users in the form of:

• configuring new rules,
• reconfiguring old rules,
• handling numerous new reports due to better (correct) coverage,
• (in some cases) adding theparserOptions.lib to silence some false-positives.

We're going to have to do a 4.0 release v soon due to the optional chain and class property AST changes, so we can hold off on this until then