Update dependencies and remove unused ones

[FlorianSW]

During this I also commited the package-lock.json file, which is recommended by npm guys. This pins our dependencies to specific versions.

Fixes #173

[digitaldan]

Thanks! I notice a few major version increases in libraries, just curious how much of the system was tested, like email templates and other less obvious parts? The reason I ask is the last time we upgraded all the packages, little things broke everywhere :-)

[FlorianSW]

I clicked through each view of the web frontend and tested all functionality I know (except OAuth2 apps itself, this would be something, which needs to be tested by someone who might have it setup locally already). I also haven't tested the stuff, that is not reachable from the frontend (e.g. the mentioned e-mail templates). So it might be good if someone else would be able to check all functions just to be save :)

[marziman]

@FlorianSW,

thats risky. As @digitaldan mentioned this can lead to serious issues.

Can we first have this longer running with some tests.

I can try it out these days.

[digitaldan]

@FlorianSW no worries, I will make sure I test the lesser used parts for this PR on my personal system.