Improve logging on build failure by displaying file contents of `meson-log.txt`

The current output from `pip` when encountering a build error is very poor. gh-231 will fix one part of that, by reducing the traceback of irrelevant pip/meson-python internals. There is a second part however which we need to improve on, which is showing the actual root cause of a build failure when possible. Now what happens is the user sees something like:

```
../../scipy/meson.build:40:0: ERROR: Command "/usr/bin/python3 -c import os; os.chdir(".."); import numpy; print(numpy.get_include())" failed with status 1.

A full log can be found at /tmp/pip-install-3okqoo15/scipy_a5afe2fae16c4250875f20d9db43706f/.mesonpy-u88p7q3f/build/meson-logs/meson-log.txt
```
and is then left wondering "_why does `import numpy` fail, given `numpy` is a build dependency?"_. The answer is in `meson-log.txt`, which `pip` has unhelpfully already cleaned up. So it's impossible to diagnose the issue (latest example for scipy [here](https://github.com/scipy/scipy/issues/16784#issuecomment-1352898268)).

Two options to improve here that I can think of:
1. Don't clean up the log file
2. Print to log file contents to stdout (possibly followed by repeating the root cause from the original stdout content)

(2) is probably better than (1).

Inizia tracciando il modo in cui vengono segnalati e ripuliti i fallimenti di build di pip provenienti da Meson, usando il percorso meson-log.txt mostrato nell’issue. Confronta la conservazione del log con la visualizzazione del suo contenuto su stdout e riproduci una build fallita per esaminare l’output disponibile. Il lavoro è completato quando gli utenti possono diagnosticare la causa principale anche dopo che la directory di build temporanea è stata ripulita.

Scritto dal modello di indicizzazione a partire dal testo della issue.