Resolve pre-MP issues.

- [ ] sol-oriens#6: Battleworld quality of life fixes
- [ ] sol-oriens#20: Transferring support ships with supply crates only decreases the supply of the original flagship
- [ ] sol-oriens#21: Sanity check: Support ships should not be transferrable between star systems
- [ ] sol-oriens#22: Sanity check: Flagships have no business owning support satellites