[WIP] Changing the balance designs of mechanic.

The old system was bad, since it allowed mechanics to make too much too cheaply.
The new system is also bad, since it makes them no more impressive than a slightly changed RnD.

Here's how the balances are planned to change
- Items would go back to the old system of anything with an origin tech. Chances of gold/silver/plasma/uranium costs would be increased
- Mechanic designs and items would need plastic. Not a lot, not in massive amounts, but always some, in balance with the other material costs. This leads mechanics to rely on cargo or botany to help build more stuff, much like the Roboticist is limited by sulphuric acid, but with no way to just build a machine to make more like with the Chem Dispenser
- Flatpacks will take multiple stages to assemble. Might or might not come with instructions.

Plans:
- [x] Add plastics to costs and map
- [x] Balance plastic costs to be in line with total material costs
- [x] Add flatpack staging to construction
- [x] Add instructions to flatpacks.
- [x] Changelog