Absorb Qt Creator's QmlJS tool into standard QML tools

Qt Creator has a tool based on JSLint for static analysis of QML/JavaScript code: https://doc.qt.io/qtcreator/creator-checking-code-syntax.html#javascript-and-qml-error-codes

There is some overlap with the standard QML tools. For example:

• M300 "Unknown component" is already handled by qmllint (unresolved-type)
• M309 "Use spaces around binary operators" is already handled by qmlformat

However, there are some checks done by QmlJS that aren't currently done by the standard QML tools. For example:

• M400 "Duplicate import" (for keeping QML code clean)
• M126 "== and != perform type coercion, use === or !== to avoid it" (for avoiding common JS pitfalls)

Furthermore, there are some inconsistencies in how the checks are are configured for different tools (see QTBUG-112338 )

Suggestion

Go through every item listed at https://doc.qt.io/qtcreator/creator-checking-code-syntax.html#javascript-and-qml-error-codes and add any relevant ones to the standard QML tools. Once that's done and once QTBUG-102038 is complete, retire QmlJS.

Rationale

• We don't want to maintain multiple tools that do the same thing.
• We want the checks to keep up with the development of the QML language.
• We want the functionality to be accessible outside of Qt Creator too.