Consider changing `#[prop]` and `#[rename]` 'macro' names

[Xenira]

As the macro rework already is a big BC change we might want to consider using a more consistent naming scheme.

Maybe something like:
#[php(prop)]
#[php(rename = "foo")]
[...]

#372 (comment)

[yoramdelangen]

I was checking and playing around with the latest version (master) in the extension I am building. I noticed the class constants are automatically exposed and I cannot make them "hidden" from PHP. Would it be more consistent to have them exposed like props? Or an option to "private" the constant?

In the new improved way all methods are automatically exposed to the PHP runtime and you can make them private or protected. But props you have to "expose" in order to make them available for PHP.

Suggestions/ideas:

• Always expose anything, props, methods, constants etc. unless you define them privately/protected. #[php(hidden)] or #[php(hide)] to hide/unavailable in PHP
• Use the Rust visibility?
• Explicitly define what should be exposed

[Xenira]

I don't like the idea of #[php(hide)] as that would default to public and things should be private by default.

Id rather use the rust visibility here, but would need to look at it more closely.

[Xenira]

Did some testing on functions and something like this is easy and I kinda like it:

#[php_function)]
#[php(rename = "test_default", vis = "public")]
#[php(defaults(a = 5))]
pub fn test_default(a: i32) -> i32 {
    a
}