IPMIView: fix iKVM console

This commit fixes #26650

The main problem was that the iKVM related libraries are always loaded
from the current working directory. The bundled wrapper script makes
sure to CD to the package root folder. This is a no-go in nix as the
application writes its settings in the current working directory and the
store is read-only.

Workaround: create a directory in the users home, where the required
binaries are symlinked and is writable for the current user.

There was an additional issue that for some BMCs IPMIView relies on
the bundled `stunnel` binary to wrap the iKVM traffic in a TLS tunnel.
Therefore it has to be patched to make it executable and the `killall`
command is needed on the PATH because it is used to terminate the
`stunnel` process upon exit.