feat: add scripts to check pkg in attw / expectedVersionFailures

[hkleungai]

A much more formal script setup for #1130. See if the code makes sense to DT-tools maintainer first, then I will proceed to incorporating them into github actions.

This PR involve some refactoring on existing dtslint code. Few things you may want to take notes on.

feat(dtslint): apply mangleScopedPackage() for package name

mangleScopedPackage() from @definitelytyped/utils is used for package name. This shall faciliate code reuse.

refactor: extract functions into util folder with minor fix

Some assertions in packages/dtslint/src/index.ts is moved to packages/dtslint/src/util.ts, with small modifications.

In findDTRootAndPackageNameFrom(), the assertions are reordered, to make the code more readable.

In assertPathIsInDefinitelyTyped(), the condition is modified. Hence if a non-existing type lib is used to run test in DT, e.g. pnpm run abc, then the error is this assertion will be properly thrown. Note that it will replace the current behaviour of throwing Error: ENOENT: no such file or directory, scandir '/<root-dir>/DefinitelyTyped/types/abc' in non-existing type lib test.

feat: add scripts to check pkg in attw / expectedVersionFailures

Two relatively simple scripts are added, aiming to check (failed) package in attw.json and expectedVersionFailures.txt in future github action development.