package/eventlog: remove package

package/eventlog: remove package

Since syslog-ng 3.11.1 eventlog has been bundled with the sources.
Remove the separate package.

We don't add Config.in.legacy handling because eventlog was only used
by syslog-ng, and was not really meant to be used by anyone else, so
there is no point in warning users who had this package enabled in
their configuration that it no longer exists, as it was only used by
syslog-ng, and syslog-ng now bundles eventlog.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
[Thomas: extend explanation about why we don't have any
Config.in.legacy handling]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>