Allow to use modern ECMAScript syntax

Nowadays, Qbs relies on QuickJS engine which supports ES2023. However, the Qbs' parser doesn't seem to understand the syntax.

As a user, I want to be able to use modern ES features including, but not limited to:

• template strings
• destructuring
• rest, spread, default
• arrow functions
• let and const
• for … of loop
• nullish coalescing ( and =)
• optional chaining ?.
• exponentiation **
• symbols
• modules
• etc.

Additionally and similarly to QML, anonymous functions and arrow functions should be allowed for properties of type script. Examples:

Rule {
    // ...
    prepare: (project, product, inputs, outputs, i, o, expDepOn) => {
        return []
    }
}

Module {
    setupRunEnvironment: (_, prd, cfg) => { ... }
}

PathProbe {
    // ...
    nameFilter: f => !f.starsWith('.')  // apparently, this is incorrect because the documentation on `PathProbe.nameFilter` does not explain how to properly use it
}