oops repeat queries in productseries-milestone-table-row.pt

Oops OOPS-1430D437 show two bad things: This bug is about the repeat queries. The root problem is that the PRF, with a very generous glob will add an insane number of release to a series--the PRF probably needs to create series to organise the downloads.

For each milestone that is shown in the milestone table, the release is looked up three times and the structuralsubscription is looked up once, but never used. The MilestoneView provides the release as view/release. The other two uses must use the view's copy. The structuralsubscription is gotten because the navigation menu is used to get the edit link. A new menu is needed that only provides the edit link to ensure the extra db call is made.