[9.x] Add support for multiple hash algorithms

[medeirosinacio]

We often need the sha256 of the file, it would be interesting for Filesystem to get it.

I was always confused by the original implementation, as "hash" refers me to all sorts of algorithms. That way we don't break what already exists (md5 default) and enable hashing like sha256 or sha512.

https://www.php.net/manual/en/function.hash-algos.php

File::hash($path)
// 196b0f14eba66e10fba74dbf9e99c22f => default md5

File::hash($path, 'sha256')
// 19c451aedfb24c338a9a2a5c31d553ed77e7cdefc655035f390176ac24066051

[driesvints]

This is a breaking change to the method signature unfortunately.

[medeirosinacio]

I had done PR for version v10, but they asked to do it for v9.
Let me know if I need to change anything.

#43378 (comment)

[taylorotwell]

I think this is probably OK - unlikely it was being overwritten.