Allow libavif to install rav1e, except on manylinux2014 and aarch64

[radarhere]

Suggestion for python-pillow#5201

I presume the reason that you didn't just use "LOCAL" for rav1e is that some dependencies were missing.

This will allow libavif to install rav1e itself - except on manylinux2014, where an initial attempt found a problem with perl, and aarch64, where the time taken was excessive. However, manylinux2014 will only be needed for a few more months, and aarch64 might become faster in the near future.

[fdintino]

Up until 8 months ago I was installing build dependencies and building rav1e in pillow-avif-plugin, but I switched to the pre-built binaries because it takes an eternity to build it in qemu virtualization. This was the workaround I had for the perl issue

https://github.com/fdintino/pillow-avif-plugin/blob/616b64091fc3ec217c0458262ffcb5d22ce9d792/wheelbuild/config.sh#L417-L419

Since the performance issues forced me to use pre-built binaries for aarch64, I figured it was simpler to do so for all environments. But at the time there wasn't a LOCAL build option in libavif; I'm actually the one who added it. Now that it exists I don't think there's any reason not to build it.