gitlab: commit notification should only include title

[blocktrron]

Currently the notification generated from a new commit includes the full commit message. This is not ideal for a quick notification.

Instead, I think it would be better to only use the commit title for notification purposes.

[herbetom]

This line seems relevant: https://github.com/fleaz/CptHook/blob/master/input/gitlab.go#L138

[fleaz]

@herbetom That's indeed the template which gets used for the commit message but you can't call arbitrary functions like e.g. split in a template.

The two options I see are either a custom template function like firstLine which we then can call in the template or we tackle this in line 411 and split the commit message before loading the data into the template.

[herbetom]

I only looked for maybe 30s for that line. My "idea" was that you could insert instead of Message something diffrent. But since Message isn't used somewhere else i would rename Message in 138 to title and split it in 411 (and also rename it). Or just add another line around 411 for the title and keep Message arround for the future.

[fleaz]

Fixed in #60