Initial proposal to differentiate sam only and sat only tests

Now tests can use decorators to run/skip tests basead on server modes:
- runIf('sam') - runs only on sam server
- runIf('sat') - runs only on sat server
- no decoractor - runs on all server modes
`mode = conf.properties.get('main.project')` is error proof (will return None if the key is not defined). Also allows to specify a default value as second argument.