Tentative approach to have RGS store a fraction of the team's build point pool.

The fraction is proportional to the part of the teams total earnings that was
acquired by the RGS in question. The initial build points (including those used
by layout structures) count as acquired, so losing RGS early on isn't punished.

Whenever a RGS is destroyed or deconstructed, its share is distributed evenly
by removing it from the account of total build points acquired.

The implementation is currently lacking a proper visualization.