Research speed limits

**What do you want to see?**
Each tech area should have a formula for the maximum number of research points that can be applied to it in one turn, depending on things like tech level, racial traits, and cultural achievements (we need those from SE5!)

**How would it help players?**
Prevent tech rushing which is cheesy. Encourage players to diversify their research.

**Alternatives**
Diminishing returns on research points applied to a tech in one turn? But that could be confusing.

**Screenshots and mockups**
The idea came from FreeOrion so go check that out!

**Things to consider**
???

**Related issues**
N/A