Deprecate linting without type information

[ajafff]

Motivation:

• There's a lot of code related to linting without type information.
• Some rules work slightly different with and without type information
  • this might still be the case if we keep the current behavior of linting without type information if the file has // @ts-nocheck
• Additional testing overhead
• Linting without type information has no real benefit besides a little less startup time
• If you use TypeScript, you should also have a tsconfig.json or jsconfig.json
• Automatically looking for a tsconfig.json if no files are listed can be surprising
  • especially if you get an error like Options '--ext' and '--project' cannot be used together even though you didn't explicitly enable --project
• Certain features don't work without type information
  • Caching Add caching based on file content and external references #752 needs a Program
  • Globbing doesn't use the FileSystem abstraction. although there is WIP: use FileSystem for globbing #418 to fix this, I'd rather not spend too much time on this
  • Watch mode (once implemented) would need a Program
• Linting in editors also works with type information out of the box when using the LanguageService plugin
• Makes the documentation a less confusing
• Makes integrating @typescript-eslint/parser and @typescript-eslint/eslint-plugin easier (Investigate adding compatibility for ESLint rules #517)

TBD:

What to do with the current behavior regarding // @ts-nocheck?

• keep as is, rules still need to check if type information is available
• remove it, always use type information, makes rules a lot easier
• completely ignore these files? OTOH could have added a disable comment for the linter as well
• make it configurable
  • name?
  • what are the options to choose? "lint all files" vs. "lint only checked files"