[Fix]: Fixed some components not having the correct information

[douxxtech]

This PR fixes:

• The Server: header being sent empty. Now either has (again) the SERVER_NAME config value, or NASMServer/<ver>
• The logged IP being empty if USE_X_REAL_IP was set to false
• The Server name: of the config dump of the startup debug logs not taking account of SERVER_NAME (even though the internal logic was)

[github-actions]

START + GET /: 166 syscalls
Fastest: 0.000017s (fstat)
Slowest: 0.901130s (accept)

threads: 4 (auto), conns: 50, duration: 20s

[wrk]
Running 20s test @ http://127.0.0.1:8080/
  4 threads and 50 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     4.81ms    9.48ms 213.81ms   99.42%
    Req/Sec     1.74k   395.02     2.68k    73.75%
  138530 requests in 20.04s, 212.17MB read
  Socket errors: connect 0, read 1360, write 0, timeout 0
Requests/sec:   6910.96
Transfer/sec:     10.58MB