[Building Sakai] Create new Plugin

[Marcel Drachmann]

Hi Sakai Devs,

I try to create a new Sakai plugin for 2.9.2 since some days, but I 
could not find exact information on how to do it. Please point me in the 
right direction.

I want it to be a Spring MVC project, if that is important.

- Sakai App Builder seems to be outdated.
- Sakai Spring MVC Maven Archetype goes to the right direction, but 
without documentation I do not know which file does what and how to 
extend it in the right way. I need more information on how to integrate 
it with core Sakai.
- Sakai Sample Code seems to be outdated too.

So please give me a hint on realiable information
- how to structure a new sakai plugin
- which files are necessary for what
- how to access and integrate with core Sakai.

Thanks a lot for your help!

Cheers,
Marcel