Add more warnings to be able to better diagnose network issues

The purpose if this task is to add more warnings, when log_warnings has a value of 4 or more, to get a better understanding of why connections are disconnected.

When having global.log_warnings >=4, one will get the following errors log in case of communications issues:

2024-03-02 16:17:40 8 [ERROR] mariadbd: Could not read packet: fd: 52 closed: 0 alarmed: 0 remain: 4 errno: 104 vio_errno: 1158 length: -1
2024-03-02 16:18:09 7 [ERROR] mariadbd: Could not write packet: fd: 20 closed: 0 alarmed: 0 errno: 32 vio_errno: 1160 length: 182

In addition, all communication errors are written to the general log if global.log_warnings >=4.