feat: consume new scope analysis package

[bradzacher]

Fixes #1856

• switch parser to use scope-manager
  • I was able to delete almost all of the snapshots from parser, because they were (pretty useless and unreviewed) snapshots of the scope tree from every single shared-fixture.
• Fix up rules:
  • no-unused-vars
    • this exposed so many bugs in the tests themselves - so many unused generic type parameters (function foo<T>() {} and class Foo<T> {}).
  • no-undef
  • no-shadow
    • define an extension rule to handle this 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 the parserOptions.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

[typescript-eslint]

Thanks for the PR, @bradzacher!

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The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[codecov]

Codecov Report

Merging #2039 into v4 will decrease coverage by 0.07%.
The diff coverage is 92.30%.

@@            Coverage Diff             @@
##               v4    #2039      +/-   ##
==========================================
- Coverage   93.05%   92.97%   -0.08%     
==========================================
  Files         285      285              
  Lines        9109     9014      -95     
  Branches     2503     2510       +7     
==========================================
- Hits         8476     8381      -95     
- Misses        303      304       +1     
+ Partials      330      329       -1     

Flag	Coverage Δ
#unittest	92.97% <92.30%> (-0.08%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
packages/eslint-plugin/src/configs/all.ts	100.00% <ø> (ø)
...ages/eslint-plugin/src/rules/no-empty-interface.ts	95.83% <0.00%> (-0.33%)	⬇️
...nt-plugin/src/rules/no-unused-vars-experimental.ts	91.48% <ø> (ø)
packages/experimental-utils/src/ts-eslint/Scope.ts	100.00% <ø> (ø)
packages/eslint-plugin/src/rules/no-redeclare.ts	87.17% <87.17%> (ø)
...es/eslint-plugin/src/rules/no-use-before-define.ts	94.36% <87.50%> (-2.78%)	⬇️
packages/eslint-plugin/src/rules/no-unused-vars.ts	96.87% <96.00%> (+4.01%)	⬆️
packages/eslint-plugin/src/rules/no-shadow.ts	98.41% <98.41%> (ø)
... and 1 more