Implement automatic reload of TLS certificates after a crash

[renecannao]

If you are submitting a reproducible bug report, please provide:

• A clear description of the issue

ProxySQL_create_or_load_TLS() is called by proxysql during the initial bootstrap, and certificates are stored in memory.
When the process forks, the child process will inherit the certificates stored in memory.
Any call to PROXYSQL RELOAD TLS will load new certificates on the child process, but not on the parent process.
Thus, after a crash, when restarting the child will inherit the original certificates.

• ProxySQL version

All up to latest (2.7.0)

• OS version

Any

• The steps to reproduce the issue

• start proxysql in background
• generate and load new TLS certificates with PROXYSQL RELOAD TLS
• crash it (kill it with -6 or -9)
• proxysql should now have the old certificates loaded

• Possible solution

In case of crash, call ProxySQL_create_or_load_TLS() in ProxySQL_daemonize_phase3() .

Unrelated enhancement in a relevant code path:
call_execute_on_exit_failure() can report an info message during a crash, suggesting the use of execute_on_exit_failure is not present.