Better naming of implementations

[mecha]

Even as the original author of most of the classes in this package, I've often found myself annoyed at how they are named 😅 We could easily improve this using class aliases.

The proposal that I outline below stems from this viewpoint: the names should reflect what the services are. For instance:

[
    // message IS a value
	'message' => new Value('Hello'),

    // greeting IS an alias
    'greeting' => new Alias('message'),

    // username IS a global var
    'username' => new GlobalVar('username'),

    // BUT ...

    // logger is ... a constructor??
    'logger' => new Constructor(Logger::class),

    // alert_text is a ... string service??
    'alert_text' => new StringService("{0}, {1}!", [
        'message',
        'username',
    ]),

    // render_fn is a funky what??
    'render_fn' => new FuncService(['message'], function (string $message) {
        return $message;
    }),
]

It would be great if all the classes had more sensible names that better outlined what the services are, rather than what the service definitions are.

I've prepared a list of which classes I think could use a better name, along with my proposed alias names:

Current name	New Alias name
Constructor	Instance
FuncService	Callback
StringService	TemplatedString

These proposed names will help to make service definitions look more natural and declarative.

[
    // logger IS an instance
    'logger' => new Instance(Logger::class),

    // alert_text IS a templated string
    'alert_text' => new TemplatedString("{0}, {1}!", [
        'message',
        'username',
    ]),

    // render_fn IS a callback
    'render_fn' => new Callback(['message'], function (string $message) {
        return $message;
    }),
]

While we're at it, we could also alias the ArrayExtension class to ArrayPushExtension, in preparation for the new ArrayMergeExtension to create a clearer distinction between the two.

Thoughts?

[XedinUnknown]

Sounds great! I'd be happy to review and merge that.