DLPX-95109 could not find 'spa_t *' when running sdb -e 'spa' on dump

[prakashsurya]

Problem

Upstream has mandated the use of the `-F` flag to `makedumpfile`, but that flag doesn't work properly on our appliance (due to our use of the `--private-page-filter` flag, that doesn't exist upstream).

Solution

This PR copies the `kdump-tools` and `kdump-config` scripts into `delphix-platform`, such that we can modify then to suit our needs, and then overrides the `kdump-tools` service to execute our modified scripts, instead of the upstream scripts.

Testing

$ sudo systemctl cat kdump-tools
# /etc/systemd/system/kdump-tools.service
[Unit]
Description=Kernel crash dump capture service

[Service]
Type=oneshot
StandardOutput=journal+console
EnvironmentFile=/etc/default/kdump-tools
ExecStartPre=-/usr/share/kdump-tools/kdump_mem_estimator
ExecStart=/etc/init.d/kdump-tools start
ExecStop=/etc/init.d/kdump-tools stop
RemainAfterExit=yes

[Install]
WantedBy=basic.target

# /usr/lib/systemd/system/kdump-tools.service.d/override.conf
[Service]
ExecStart=
ExecStart=/var/lib/delphix-platform/kdump-tools/kdump-tools start

$ systemctl status kdump-tools
● kdump-tools.service - Kernel crash dump capture service
     Loaded: loaded (/etc/systemd/system/kdump-tools.service; enabled; preset: enabled)
    Drop-In: /usr/lib/systemd/system/kdump-tools.service.d
             └─override.conf
     Active: active (exited) since Tue 2025-08-26 16:08:49 UTC; 3min 0s ago
    Process: 806 ExecStart=/var/lib/delphix-platform/kdump-tools/kdump-tools start (code=exited, status=0/SUCCESS)
   Main PID: 806 (code=exited, status=0/SUCCESS)
        CPU: 11.103s