Request: asdf-re2c plugin and precompiled PHP binaries

### Provide environment information

```bash
Hi,

This is a feature request, not a bug report.

It's difficult to install PHP on some environments. Operating systems whose package managers are stuck at an old version of re2c, rootless environments, and ephemeral environments.

As a workaround, some ASDF users can manually download source code for re2c (they don't publish generic _binary_ archives), and follow the re2c documentation to compile and install re2c.

Can we please publish an asdf-re2c plugin, in order to make it easier to build and install PHP across more environments?

--

In fact, it would be much simpler if asdf-php gave users the option of installing PHP from precompiled binaries. That way, less compilation is required on the target environment. This matches moovweb/gvm `-B` packages and Homebrew casks.

Perhaps we could introduce an environment variable that controls whether PHP is installed from source vs precompiled binaries. I don't mind if the default remains building from source. But it's helpful to provide both options to as many platforms as possible.
```

### To Reproduce

NA

### Describe the Bug

NA

### Expected Behaviour

NA

No files, tests, or entry points are named. Start by reviewing the plugin's installation flow and decide whether the scope is an asdf-re2c plugin, precompiled PHP binaries, or both; done should mean a documented, working installation path for the selected approach.

Written by the indexing model from the issue text.