httpd: Fix of 5 CVEs

CVE-2026-28780: modproxyajp 4-byte heap buffer overflow when contacting a malicious AJP backend off-by-AJPHEADERLEN check in ajpmsgcheckheader - CVE-2026-34059: modproxyajp heap over-read in ajpparsedata on short AJP replies - CVE-2026-33006: modauthdigest used non-constant-time strcmp for...