Rpm and new structure

Changes in `celar-server-api` module

  * split generation of .war and .rpm into `war` and `rpm` modules
  * updated RPM package generation
    * added dependency on tomcat6
    * installation goes into `${celar.install.dir}` (defined in `celar-distribution` project)
    * removed RPM scripts and added them directly into POM

The changes rely on updated `celar-distribution` project.

Please review.