Add performance tests

[bonjourmauko]

Stories

Developer

When providing the WebAPI to end-user applications,
I expect openfisca's performance to be consistent,
To maintain consumer's expectations,
And so they don't move away from openfisca to another solution.

Data scientist / economist

When running simulations with large datasets,
I expect permance to scale close to O(1) with dataset size,
To actually be able to run simulations with finer data without having to buy new hardware.

TODO

• Improve dump restore #1292
• Fix enums performance #1306
• Add unit performance tests to Enum
• Add unit performance tests to EnumArray
• Add integration performance tests to simulation dump/restore
• Add an e2e simulation performance test
• Enforce performance tests on CI with a <50% threshold