After recent change `services.smokeping.enable = true;` system
started failing the build as:
```
nixpkgs-master $ nix build --no-link -f nixos system --keep-going
...
Checking that Nix store paths of all wrapped programs exist... FAIL
The path /nix/store/kr2sr80g9ny74im6m6dyh9v44hnzm261-fping-5.0/bin/fping6 does not exist!
Please, check the value of `security.wrappers."fping6".source`.
```
`fping` does not provide `fping6` binary for a while. Let's just remove it.
Closes: https://github.com/NixOS/nixpkgs/issues/138581
This fixes a regression from bb649d96b0.
There were permission problems, when the preStart script tried to copy
the smokeping.fcgi file over the old file.
The current default probe config uses the unwrapped fping binary, which
leads to an error because fping must be executed with elevated
permissions.
I fixed this by changing the path to the default binary to the
setuid-wrapped version.
In the prestart config of the smokeping service, smokeping is executed
initially. This happens as the user root and writes some files to
$smokepingHome, which can't be overwritten by the smokeping user. This
gives an error message.
I fixed this by moving the chown step after the initial smokeping runs,
so that it also affects the generated files.
The initial commit accidentally left in some commented code and if you were
using alerts, they simply didn't work.
Smokeping also includes some JS code for the webui allowing you to zoom into
graphs and it was not passed into the homedir. Additionally, generate
static html pages for other webservers to serve the cache directory.
Add additional options to specify sendmail path or mailhost and verify that both
are not set.
Add one extra config hook that allows you to bypass all of the invidual config
stanzas and just hand it a string.
