Security manager should only be activated for Bitarchive application

Currently the java security manager is activated for all applications with a custom security policy definition. Historically the only reason for using a custom security manager in NAS has been to prevent BatchJob injected code from wrecking havoc. As the usage of a security manager causes problem when trying to access files outside of the constrained policy defined in the NAS software, we should avoid using it more than absolutely necessary.

Note that the general usage of a custom security policy has been discussed in the NAS team + Kåre and the agreement is that this policy should at most be applied to the bitarchives, if not being discontinued altogether.