Move collection post serialization
Move collection post serialization

We should serialize all objects when they are still in the session. This
change remove linear number of database queries for all collection post
requests.

selahssea/ggrc-core,VinnieJohns/ggrc-core,selahssea/ggrc-core,andrei-karalionak/ggrc-core,edofic/ggrc-core,selahssea/ggrc-core,plamut/ggrc-core,j0gurt/ggrc-core,andrei-karalionak/ggrc-core,andrei-karalionak/ggrc-core,kr41/ggrc-core,VinnieJohns/ggrc-core,selahssea/ggrc-core,VinnieJohns/ggrc-core,edofic/ggrc-core,plamut/ggrc-core,plamut/ggrc-core,VinnieJohns/ggrc-core,AleksNeStu/ggrc-core,j0gurt/ggrc-core,josthkko/ggrc-core,kr41/ggrc-core,josthkko/ggrc-core,j0gurt/ggrc-core,kr41/ggrc-core,edofic/ggrc-core,josthkko/ggrc-core,AleksNeStu/ggrc-core,j0gurt/ggrc-core,AleksNeStu/ggrc-core,plamut/ggrc-core,edofic/ggrc-core,AleksNeStu/ggrc-core,andrei-karalionak/ggrc-core,josthkko/ggrc-core,kr41/ggrc-core