feat(typescript-estree): always return parserServices

[bradzacher]

BREAKING CHANGE:

previously plugins expected that parserServices would be undefined if full type information wasn't available.

Splitting these changes out of #688 to focus that PR.
The motivation behind this is that this will allow rules to consume diagnostics without needing the user to provide project, which slows down linting.

[armano2]

@bradzacher are you planning to resolve conflicts or do you want me to pick it up?

[bradzacher]

I was planning on getting back to it eventually, but it's been at a lower priority, because 3.0.0 was so far out 😅.

If you get the gist of what I was intending, then feel free to pick this up and get it ready for 3.0.0. I'd appreciate it 😄.

One important note: no-unused-vars-experimental will not require the complete type information with this change, so you should update that rule as part of this PR.

[codecov]

Codecov Report

Merging #716 into v3 will decrease coverage by 0.08%.
The diff coverage is 56.25%.

@@            Coverage Diff             @@
##               v3     #716      +/-   ##
==========================================
- Coverage   93.87%   93.78%   -0.09%     
==========================================
  Files         172      172              
  Lines        7805     7809       +4     
  Branches     2240     2243       +3     
==========================================
- Hits         7327     7324       -3     
- Misses        221      227       +6     
- Partials      257      258       +1     

Flag	Coverage Δ
#unittest	93.78% <56.25%> (-0.09%)	⬇️

Impacted Files	Coverage Δ
...es/eslint-plugin/src/configs/eslint-recommended.ts	100.00% <ø> (ø)
...mental-utils/src/eslint-utils/getParserServices.ts	18.18% <0.00%> (-15.16%)	⬇️
...-estree/src/create-program/createProjectProgram.ts	92.68% <ø> (-0.18%)	⬇️
...ges/typescript-estree/src/create-program/shared.ts	88.57% <ø> (ø)
...es/eslint-plugin/src/rules/no-unsafe-assignment.ts	80.17% <50.00%> (ø)
...nt-plugin/src/rules/indent-new-do-not-use/index.ts	98.40% <100.00%> (ø)
...nt-plugin/src/rules/no-unused-vars-experimental.ts	91.48% <100.00%> (ø)
.../eslint-plugin/src/util/explicitReturnTypeUtils.ts	100.00% <100.00%> (ø)
packages/typescript-estree/src/ast-converter.ts	100.00% <100.00%> (ø)
packages/typescript-estree/src/convert.ts	99.15% <100.00%> (ø)
... and 3 more